CN111093984A - Laminate, polarizing plate, and image display device - Google Patents

Abstract

The invention provides a laminate having a hard coat layer and capable of suppressing transfer of the shape of another object on the hard coat layer, and a polarizing plate and an image display device having the laminate. A laminate, a polarizing plate having the laminate, and an image display deviceThe body has a buffer layer, a support and a hard coating, the buffer layer being at 25 ℃ and at a frequency of 10⁴～10¹³The range of Hz has a maximum value of tan delta. Where tan δ is the ratio of the loss elasticity with respect to the storage modulus.

Description

Laminate, polarizing plate, and image display device

Technical Field

The present invention relates to a laminate, a polarizing plate, and an image display device.

Background

In image display devices such as display devices using Cathode Ray Tubes (CRTs), Plasma Displays (PDPs), electroluminescence displays (ELDs), fluorescent displays (VFDs), Field Emission Displays (FEDs), and Liquid Crystal Displays (LCDs), it is preferable to provide a hard coating film having a hard coat layer on a support (substrate) in order to prevent scratches and the like on the display surface.

For example, patent documents 1 and 2 disclose a hard coat film having a hard coat layer on one surface of a substrate and a urethane resin layer on the other surface.

Prior art documents

Patent document

Patent document 1: international publication No. 2014/141866

Patent document 2: japanese patent laid-open publication No. 2016-060117

Patent documents 1 and 2 describe a hard coat film and improve impact resistance and scratch resistance, but through studies by the present inventors, it has been found that when a hard coat layer is scratched while being in contact with another object, there is a new problem that the shape of the object is transferred to the hard coat layer.

For example, when a notebook computer (notebook PC) having a hard coat film on the display surface is carried in a folded state, there are problems in that traces of a keyboard are transferred to the display surface by applying a load from the outside, or a foreign substance is interposed between the display and the keyboard to cause a dent or a scratch on the display surface (hereinafter, also referred to as "keyboard transfer"). Further, for example, when a smartphone having a hard coat film on the display surface is loaded in a case and transported, a load is applied to the case, and the shape of the inside of the case is sometimes transferred to the display surface.

Disclosure of Invention

Technical problem to be solved by the invention

The present invention has been made in view of the above problems, and an object thereof is to provide a laminate having a hard coat layer and capable of suppressing transfer of the shape of another object to the hard coat layer, and a polarizing plate and an image display device having the laminate.

Means for solving the technical problem

As a result of intensive studies, the present inventors have found that the above problems can be solved by a laminate having a buffer layer having a maximum value of tan δ in a specific frequency region.

That is, the above problem can be solved by the following means.

<1> a laminate having a cushion layer, a support and a hard coat layer, wherein in the laminate,

the buffer layer is at 25 deg.C and frequency 10⁴～10¹³The range of Hz has a maximum value of tan delta.

Wherein tan δ is a ratio of a dissipation modulus to a storage modulus.

<2> the laminate according to <1>, wherein,

the maximum value of tan δ is 0.1 or more.

<3> the laminate according to <1> or <2>, wherein,

the storage modulus of the buffer layer at a frequency representing the maximum value of tan δ is 30MPa or more.

<4> the laminate according to any one of <1> to <3>, wherein,

the thickness of the buffer layer is 10 to 200 μm.

<5> the laminate according to any one of <1> to <4>, wherein,

the buffer layer comprises a block copolymer of methyl methacrylate and n-butyl acrylate.

<6> the laminate according to any one of <1> to <5>, which further has an inorganic oxide layer.

<7> the laminate according to any one of <1> to <6>, wherein,

the hard coat layer contains a cured product of a polymerizable compound.

<8> a polarizing plate, wherein,

the laminate of any one of <1> to <7> has a polarizer.

<9> an image display device comprising the laminate of any one of <1> to <7> or the polarizing plate of <8 >.

In the present specification, a numerical range expressed by "to" means a range in which numerical values before and after "to" are included as a lower limit value and an upper limit value.

In the present specification, "(meth) acrylate" is used in the meaning of either one or both of acrylate and methacrylate. Also, "(meth) acryloyl group" is used in one or both of the meanings of acryloyl and methacryloyl. "(meth) acrylic acid" is used in either or both of the meanings of acrylic acid and methacrylic acid.

In the present specification, unless otherwise specified, the weight average molecular weight (Mw) can be measured in terms of polystyrene by Gel Permeation Chromatography (GPC). In this case, the GPC apparatus used HLC-8220(TOSOH CORPORATION), the column used G3000HXL + G2000HXL, at 23 ℃ at a flow rate of 1mL/min, as Refractive Index (RI) for detection. The eluent can be selected from THF (tetrahydrofuran), chloroform, NMP (N-methyl-2-pyrrolinone), m-cresol/chloroform (Shonan Wako Junyaku k.k.) and THF is used as long as it is dissolved.

Effects of the invention

The present invention can provide a laminate having a hard coat layer and capable of suppressing transfer of the shape of another object to the hard coat layer, and a polarizing plate and an image display device each having the laminate.

Drawings

Fig. 1 is a schematic sectional view showing the structure of a laminate of the present invention.

Fig. 2 is a schematic cross-sectional view showing an embodiment of the structure of the laminate of the present invention having an inorganic oxide layer.

FIG. 3 is a graph showing the relationship between the frequency of the buffer layer at 25 ℃ and tan. delta.

Detailed Description

The present invention will be described in detail below.

[ laminate ]

The laminate of the present invention comprises a cushion layer, a support and a hard coat layer, wherein,

buffer layer at 25 ℃ at frequency 10⁴～10¹³The range of Hz has a maximum value of tan delta.

Where tan δ (loss tangent) is the ratio of the energy dissipation modulus to the storage modulus.

Fig. 1 shows an example of a preferred embodiment of the laminate of the present invention. The laminate 4A shown in fig. 1 is a laminate having a support 2A, a hard coat layer (hereinafter, also referred to as an "HC layer") 1A disposed on one side of the support 2A, and a cushion layer 3A disposed on the surface opposite to the surface on which the HC layer 1A is formed. Another preferred embodiment of the laminate of the present invention is a laminate having a cushion layer, a support disposed on one side of the cushion layer, and a hard coat layer disposed on the side opposite to the side on which the support is disposed.

With the laminate of the present invention having the above-described structure, transfer of the shape of another object to the hard coat layer can be sufficiently suppressed.

As an example of the transfer of the shape of another object onto the hard coat layer, it is considered that the keyboard transfer is caused by, for example, an impact when the keyboard is brought into contact with the display and friction of the keyboard on the display surface after the contact. It is considered that the frequency of vibration generated by transportation or the like is usually 1 to 10³Hz (refer to JIS Z0232, AS TMD4169, etc.). In the context of the invention, it is assumed, for example, to clamp the support and to have a value of 10 at 25 ℃ on the side opposite the hard coating⁴～10¹³In HzThe buffer layer having the maximum value of tan δ in the range can alleviate the above-described impact and friction, and can suppress transfer of the shape of another object on the hard coat layer (for example, keyboard transfer).

Further, the laminate of the present invention having the above-described structure is also excellent in cushioning properties against falling of an object (resistance to falling balls).

In the present invention, a graph of frequency-tan δ was prepared in the following manner with respect to the relationship between the frequency of the buffer layer at 25 ℃ and tan δ, and the maximum value of tan δ and the frequency of the maximum value were obtained.

(method of preparing sample)

A coating liquid obtained by dissolving or melting a material for forming a buffer layer in a solvent is applied to the release-treated surface of a release sheet subjected to a release treatment so that the thickness after drying becomes 10 to 50 [ mu ] m, and the coating liquid is dried, and then the buffer layer is released from the release sheet to prepare a test piece of the buffer layer.

(measurement method)

The test piece was subjected to humidity conditioning in an environment of 25 ℃ and 60% relative humidity for 2 hours or more using a dynamic viscoelasticity measuring apparatus (DVA-225 manufactured by ITS japan inc., ltd.) and measured under the following conditions in the "step temperature rise and frequency dispersion" mode, and then main curves of tan δ, storage modulus E', and dissipation modulus E "with respect to a frequency at 25 ℃ were obtained by compiling" main curves ". From the obtained master curve, the maximum value of tan δ and the frequency of the maximum value were obtained.

Sample preparation: 5mm x 30mm

Distance between the clamps: 20mm

Setting strain: 0.10 percent

Measuring the temperature: 40 ℃ below zero to 40 DEG C

Temperature rising conditions are as follows: 2 ℃/min

Buffer layer at 25 ℃ at frequency 10⁴～10¹³Within the range of Hz, at least 1 maximum of tan delta, at a frequency of 10⁴～10¹³The range of Hz may also have 2 or more maximum values of tan δ. And, at frequencies other than 10⁴～10¹³Other than HzMay also have a maximum value of tan δ, which may also be a maximum value.

The buffer layer is at 25 deg.C, preferably at frequency 10⁴～10¹³Has at least 1 maximum value of tan delta in the range of Hz, more preferably at a frequency of 10⁵～10¹²In the range of Hz, at least 1 maximum of tan delta, more preferably at a frequency of 10⁶～10¹¹Within the range of Hz there is at least 1 maximum of tan delta.

From the viewpoint of buffering, the maximum value of tan δ of the buffer layer at 25 ℃ is preferably 0.1 or more, and more preferably 0.2 or more. From the viewpoint of hardness, the maximum value of tan δ of the buffer layer at 25 ℃ is preferably 3.0 or less.

The storage modulus (E') of the buffer layer at a frequency representing the maximum value of tan δ is preferably 30MPa or more. Since E' of the buffer layer at a frequency indicating the maximum value of tan δ is 30MPa or more, the displacement amount with respect to external stress does not increase, and thus, the laminate and the display using the laminate as a front panel are less likely to be damaged due to deformation. The E' of the buffer layer at a frequency representing the maximum value of tan δ is more preferably 50MPa or more. Further, from the viewpoint of buffering, the E' of the buffer layer in the frequency representing the maximum value of tan δ is not particularly limited, but 10³Practical under MPa.

The components and preparation of each layer constituting the laminate of the present invention will be described in detail below.

(1) Buffer layer

(Material of buffer layer)

The buffer layer included in the laminate of the present invention may be made of a resin or an elastomer (including an oil-extended rubber) as long as it provides a maximum value of tan δ in the frequency region. When the laminate is used as a protective film, a polarizing plate, a front panel, or the like of an image display device, it is preferable that the buffer layer has a structure capable of securing visibility of display contents and preventing damage to thin glass laminated on the surface of the image display device due to pressing or collision of the protective film, the polarizing plate, the front panel, or the like.

Examples of the resin include 1, 2-polybutadiene resins, polyolefin resins such as ethylene-vinyl acetate copolymers (EVA, generally containing 3 mass% or more of vinyl acetate units) and polyethylene, polyvinyl chloride resins, polystyrene resins, polyacrylic resins ((meth) acrylic ester resins and the like), vinyl ester resins (other than EVA), saturated polyester resins, polyamide resins, fluorine resins (polyvinylidene fluoride and the like), polycarbonate resins, polyacetal resins, epoxy resins, (meth) acrylic resins, unsaturated polyester resins, and silicone resins.

Among these resins, (meth) acrylic resins and the like are preferable.

Examples of the elastomer include a polymer or a block copolymer of a conjugated diene, an acrylic polymer or a block copolymer, a styrene polymer or a block copolymer, a block copolymer of an aromatic vinyl compound and a conjugated diene, a hydrogen additive of a polymer or a block copolymer of a conjugated diene, a hydrogen additive of a block copolymer of an aromatic vinyl compound and a conjugated diene, an ethylene- α -olefin copolymer, a polar group-modified olefin copolymer, an elastomer including a polar group-modified olefin copolymer and a metal ion and/or a metal compound, a nitrile rubber such as an acrylonitrile-butadiene rubber, a butyl rubber, an acrylic rubber, a thermoplastic polyolefin elastomer (TPO), a thermoplastic polyester elastomer (TPEE), a polyamide elastomer (TPEE), a thermoplastic elastomer such as a diene elastomer (1, 2-polybutadiene), a silicone elastomer, a fluorine elastomer, and the like.

Among these elastomers, acrylic polymers or block copolymers, styrene polymers or block copolymers, and silicone elastomers are preferable, and acrylic block copolymers and styrene block copolymers are particularly preferable. Examples of the acrylic block copolymer include a block copolymer of methyl methacrylate and n-butyl acrylate (also referred to as "PMMA-PnBA copolymer"). Examples of the styrenic block copolymer include a block copolymer of styrene and isoprene or butylene. The resin or elastomer that can contain the cushion layer can be synthesized by a known method, and a commercially available product can be used. Examples of commercially available products include KURARITY LA2140e, KURARITY LA2250, KURARITY LA4285, HYB RAR5127, and HYBRAR7311F (product name, manufactured by Kuraray co.

From the viewpoint of the balance between solubility in a solvent and hardness, the weight average molecular weight of the resin or elastomer is preferably 10⁴～10⁶More preferably 5X 10⁴～5×10⁵。

The cushioning layer included in the laminate of the present invention has a maximum value of tan δ in the above frequency region, but it is presumed that the maximum value of tan δ in which frequency region is located is related to the mobility of the main chain or side chain of the resin or elastomer constituting the cushioning layer. Therefore, it is presumed that the resin or the elastomer having the same structure has a maximum value of tan δ in the same frequency region.

The content of the resin or elastomer in the cushion layer is preferably 50 to 100 mass% with respect to the total mass of the cushion layer.

(additives)

The cushion layer may be made of only the resin or the elastomer, but may contain an additive in addition to the resin or the elastomer. Examples of the additives include adhesion improvers, softeners, plasticizers, lubricants, crosslinking agents, crosslinking aids, photosensitizers, antioxidants, anti-aging agents, heat stabilizers, flame retardants, antibacterial or antifungal agents, weather resistant agents, ultraviolet absorbers, tackifiers, nucleating agents, pigments, dyes, organic fillers, inorganic fillers, silane coupling agents, and titanium coupling agents. Further, a polymer other than the above-mentioned resin or elastomer may be contained.

The adhesion improver to be added to the cushion layer is not particularly limited, but for example, rosin ester resin, hydrogenated rosin ester resin, petrochemical resin, hydrogenated petrochemical resin, terpene phenol resin, aromatic modified terpene resin, hydrogenated terpene resin, alkylphenol resin, etc. can be used, and 1 kind or 2 or more kinds can be used in combination. Examples of commercially available products include SUPER ESTER L, SUPER ES TER A-18, SUPER ESTER A-75, SUPER ESTER A-100, SUPER ESTER A-115, SUPER ESTER A-125(Arakawa Chemical Co., Ltd., product name, manufactured by Ltd.).

The content of the additive other than the above-described resin or elastomer in the cushion layer is preferably 50 mass% or less with respect to the total mass of the cushion layer.

(method of Forming buffer layer)

The method for forming the buffer layer is not particularly limited, and examples thereof include a coating method, a casting method (a solvent-free casting method and a solvent casting method), a pressing method, an extrusion method, an injection molding method, and an inflation method. Specifically, a liquid material in which the material for forming the buffer layer is dissolved or dispersed in a solvent or a melt of the material for forming the buffer layer is prepared, and then the liquid material or the melt is applied to one side surface (the surface opposite to the surface on which the hard coat layer is formed) of a support body described later, and thereafter, the solvent is removed as necessary, whereby a laminate in which the buffer layer is laminated can be produced.

The liquid material or the melt is applied to the release-treated surface of the release sheet subjected to the release treatment and dried to form a sheet including the cushion layer, and the cushion layer of the sheet is bonded to the support, whereby a laminate having the cushion layer laminated thereon can also be produced.

When the cushion layer is made of the above resin, the cushion layer may be made of an uncrosslinked resin or may be made of a resin at least partially crosslinked. The method of crosslinking the resin is not particularly limited, and examples thereof include methods selected from electron beam irradiation, ultraviolet irradiation, and a method using a crosslinking agent (e.g., an organic peroxide). When crosslinking of the resin is performed by electron beam irradiation, crosslinking can be formed by irradiating the obtained buffer layer (before crosslinking) with an electron beam using an electron beam irradiation apparatus. In the case of ultraviolet irradiation, the obtained buffer layer (before crosslinking) is irradiated with ultraviolet rays by an ultraviolet irradiation apparatus, whereby crosslinking can be formed by the effect of the photosensitizer incorporated as needed. In the case of using a crosslinking agent, the obtained buffer layer (before crosslinking) is usually heated in an atmosphere free of air such as a nitrogen atmosphere, and crosslinking can be formed by the effect of the crosslinking assistant and the crosslinking agent such as an organic peroxide, which is blended as necessary.

(film thickness)

The thickness (thickness) of the buffer layer included in the laminate of the present invention is preferably 5 μm or more, more preferably 8 μm or more, even more preferably 10 μm or more, and particularly preferably 25 μm or more, from the viewpoint of suppressing transfer of the shape of another object to the hard coat layer. From the viewpoint of film hardness, the thickness is preferably 200 μm or less.

(2) Support body

(Material of support)

The material of the support (hereinafter also referred to as a resin film) used in the present invention is not particularly limited.

The support is preferably transparent. In the present specification, the term "transparent" means that the visible light transmittance is 80% or more, preferably 90% or more.

Examples of the resin film include cellulose ester resin films such as acrylic resin films, Polycarbonate (PC) resin films, and triacetyl cellulose (TAC) resin films, polyethylene terephthalate (PET) resin films, polyolefin resin films, polyester resin films, polyimide resin films, and acrylonitrile-butadiene-styrene copolymer films, and films selected from acrylic resin films, cellulose ester resin films, polyethylene terephthalate resin films, polyimide resin films, and polycarbonate resin films are preferable.

From the viewpoint of moisture permeability, a cellulose ester resin film is more preferable. Further, from the viewpoint of the cushioning property, a polyimide resin film is preferable.

The acrylic resin film is a resin film of a polymer or copolymer formed from 1 or more compounds selected from the group consisting of acrylic acid esters and methacrylic acid esters. An example of the acrylic resin film is a polymethyl methacrylate (PMMA) film.

The weight average molecular weight of the resin is preferably 10,000 to 1000,000, more preferably 100,000 to 1000,000.

(Structure of resin film)

The structure of the resin film is not limited, and may be a single layer or a laminate film composed of 2 or more layers. In the case of a 2-layer or more laminated film, the number of layers of the laminated film is preferably 2 to 10, more preferably 2 to 5, and further preferably 2 or 3. In the case of 3 or more layers, the outer layer and the layer other than the outer layer (e.g., core layer) are preferably films having different compositions. Also, the outer layers are preferably films of the same composition.

(additives)

The resin film contains an additive in addition to the above resin. Examples of the additive include inorganic particles, matting particles, ultraviolet absorbers, fluorine-containing compounds, surface conditioners, leveling agents, and the like described in the description of the hard coat layer to be described later.

(thickness of support)

The thickness of the support is preferably 80 μm or more, more preferably 90 μm or more, and particularly preferably 100 μm or more, from the viewpoint of cushioning properties and resistance to falling balls. From the viewpoint of brittleness, the thickness is preferably 300 μm or less, and more preferably 200 μm or less.

(method for producing resin film)

The resin film can be formed by any known method, and examples thereof include a melt film-forming method and a solution film-forming method.

(3) Hard coat (HC layer)

The laminate of the present invention has a hard coat layer (HC layer). The HC layer is preferably disposed on one side of the support.

The HC layer used in the present invention can be obtained by irradiating the curable composition for forming an HC layer with active energy rays to cure the composition, and in the present specification, "active energy rays" refer to ionizing radiation and include X-rays, ultraviolet rays, visible light, infrared rays, electron beams, α rays, β rays, γ rays, and the like.

The curable composition for forming an HC layer used for forming an HC layer contains at least one component having a property of being cured by irradiation with an active energy ray (hereinafter, also referred to as "active energy ray-curable component"). The active energy ray-curable component is preferably at least one polymerizable compound selected from the group consisting of radical polymerizable compounds and cation polymerizable compounds. In the present specification, the term "polymerizable compound" refers to a compound containing 1 or more polymerizable groups in1 molecule. The polymerizable group means a group capable of participating in a polymerization reaction. The polymerization reaction may be any of various polymerization reactions such as radical polymerization, cationic polymerization, and anionic polymerization.

The HC layer in the laminate of the present invention preferably contains a cured product of a polymerizable compound.

The polymerizable compound is preferably a polymerizable compound having 2 or more ethylenically unsaturated groups in1 molecule. The ethylenically unsaturated group means a functional group having an ethylenically unsaturated double bond. Examples of the polymerizable compound having 2 or more ethylenically unsaturated groups in1 molecule include esters of polyhydric alcohols and (meth) acrylic acid [ for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, hexanediol di (meth) acrylate, 1, 4-cyclohexane diacrylate, neopentyltetraol tetra (meth) acrylate, neopentyltetraol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, neopentyltetraol tetra (meth) acrylate, neopentyltetraol penta (meth) acrylate, neopentyltetraol hexa (meth) acrylate, 1, 2, 3-cyclohexane tetramethylacrylate, polyurethane polyacrylate, poly (urethane acrylate), Polyester polyacrylate ], ethylene oxide modified products of the above esters, polyethylene oxide modified products, caprolactone modified products, vinylbenzene and its derivatives [ e.g., 1, 4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1, 4-divinylcyclohexanone ], vinylsulfone (e.g., divinylsulfone), acrylamide (e.g., methylenebisacrylamide), and methacrylamide.

The polymerizable compound may be a compound having a cationically polymerizable group. The cationic polymerizable group preferably includes an oxygen-containing heterocyclic group and a vinyl ether group. The cationically polymerizable compound may contain 1 or more oxygen-containing heterocyclic groups and 1 or more vinyl ether groups in1 molecule.

The oxygen-containing heterocycle may be a monocyclic ring or a condensed ring. Also, it is preferable to have a bicyclic skeleton. The oxygen-containing heterocyclic ring may be a non-aromatic ring or an aromatic ring, and is preferably a non-aromatic ring. Specific examples of the monocyclic ring include an epoxy ring, a tetrahydrofuran ring and an oxetane ring. Examples of the compound having a bicyclic skeleton include oxabicyclo. The cationically polymerizable compound contains a cationically polymerizable group containing an oxygen-containing heterocycle as a substituent having a valence of 1 or as a polyvalent substituent having a valence of 2 or more. The fused ring may be fused with 2 or more oxygen-containing heterocyclic rings, or may be fused with 1 or more ring structures other than the oxygen-containing heterocyclic ring. The ring structure other than the oxygen-containing heterocyclic ring is not limited to the above, but a cycloalkane ring such as a cyclohexane ring can be mentioned.

The polymerizable compound may be a compound having both a cationically polymerizable group and a radically polymerizable group (preferably, an ethylenically unsaturated group).

Specific examples of the cationically polymerizable compound containing an oxygen-containing heterocycle as a cationically polymerizable group include 3, 4-epoxycyclohexylmethyl methacrylate (commercially available products such as Daicel Corporation Co., Ltd., CY CLOMER M100 manufactured by Ltd.), 3, 4-epoxycyclohexylmethyl-3 ', 4' -epoxycyclohexanecarboxylate (commercially available products such as UVR6105, UVR6110 and Daicel Corporation Co., Ltd., CELLOXIDE2021 manufactured by Ltd.), bis (3, 4-epoxycyclohexylmethyl) adipate (UVR 6128 manufactured by Union Carbide Corporation), vinylcyclohexene monoepoxide (commercially available products such as Daicel Corporation Co., Ltd., CELLOXIDE2000 manufactured by Ltd.), epsilon-caprolactone-modified 3, 4-epoxycyclohexylmethyl 3 ', 4' -epoxycyclohexanecarboxylate (e.g., Daicel Co., Ltd., CELLOXIDE2081 manufactured by Ltd.), 1-methyl-4- (2-epoxyethyl) -bicyclo [ 4- (2-methyl-ethyl) -7-methyl-ethyl ] acrylate, 1, 0] heptane (e.g., Daicel Corporation Co., Ltd. CELLOXIDE3000), 7 '-dioxo-3, 3' -bis [ bicyclo [4.1.0] heptane ] (e.g., Daicel Corporation Co., Ltd. CELLOXIDE8000), 3-ethyl-3-hydroxymethyloxetane, 1, 4-bis { [ (3-ethyl-3-oxetanyl) methoxy ] methyl } benzene, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, and bis [ 1-ethyl (3-oxetanyl) ] methyl ether, etc.

The content of the polymerizable compound is preferably 15 to 99% by mass, and more preferably 30 to 99% by mass, based on the total solid content in the curable composition for forming an HC layer. The solid component means a component other than the solvent.

The HC layer used in the present invention may have a 1-layer structure or a laminated structure having 2 or more layers as described below.

1)1 layer structure

As a preferred embodiment of the curable composition for forming an HC layer having a 1-layer structure, a first embodiment can be mentioned which comprises at least one polymerizable compound having 2 or more ethylenically unsaturated groups in1 molecule. The ethylenically unsaturated group means a functional group having an ethylenically unsaturated double bond. In addition, as a second embodiment, there can be mentioned a curable composition for forming an HC layer, which contains at least one radical polymerizable compound and at least one cation polymerizable compound.

The curable composition for forming an HC layer according to the first embodiment is described below.

Examples of the polymerizable compound having 2 or more ethylenically unsaturated groups in1 molecule contained in the curable composition for forming an HC layer according to the first embodiment include esters of a polyol and (meth) acrylic acid [ e.g., ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, hexanediol di (meth) acrylate, 1, 4-cyclohexane diacrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, mixtures thereof, and the like, 1, 2, 3-cyclohexane tetramethylacrylate, polyurethane polyacrylate, polyester polyacrylate ], ethylene oxide modified products, polyethylene oxide modified products or caprolactone modified products of the above esters, vinylbenzene and its derivatives [ e.g., 1, 4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1, 4-divinylcyclohexanone ], vinyl sulfone (e.g., divinylsulfone), acrylamide (e.g., methylenebisacrylamide), and methacrylamide.

The polymerization of the polymerizable compound having an ethylenically unsaturated group can be performed by irradiation with active energy rays in the presence of a radical photopolymerization initiator. As the radical photopolymerization initiator, a radical photopolymerization initiator described later is preferably used. In addition, as for the content ratio of the radical photopolymerization initiator to the polymerizable compound having an ethylenically unsaturated group in the curable composition for forming an HC layer, it is preferable to apply the description of the content ratio of the radical photopolymerization initiator to the radical polymerizable compound described later.

Next, the curable composition for forming an HC layer according to the second embodiment will be described.

The curable composition for forming an HC layer according to the second embodiment contains at least one radical polymerizable compound and at least one cation polymerizable compound. A preferred embodiment includes a curable composition for forming an HC layer, the curable composition for forming an HC layer including:

a radical polymerizable compound containing 2 or more radical polymerizable groups selected from the group consisting of an acryloyl group and a methacryloyl group in1 molecule; and

a cationically polymerizable compound.

The curable composition for forming an HC layer preferably contains a radical photopolymerization initiator and a cationic photopolymerization initiator. As a preferred embodiment of the second embodiment, there can be mentioned a curable composition for forming an HC layer, the curable composition for forming an HC layer comprising:

a radical polymerizable compound containing 2 or more radical polymerizable groups selected from the group consisting of an acryloyl group and a methacryloyl group in1 molecule;

a cationically polymerizable compound;

a free radical photopolymerization initiator; and

a cationic photopolymerization initiator. Hereinafter, this embodiment will be described as a second embodiment (1).

In the second embodiment (1), the radical polymerizable compound preferably contains 2 or more radical polymerizable groups in1 molecule and 1 or more urethane bonds in1 molecule.

In another preferred embodiment of the second embodiment, there is provided a curable composition for forming an HC layer, the curable composition for forming an HC layer including:

a) a cationically polymerizable compound containing an alicyclic epoxy group and an ethylenically unsaturated group, wherein the number of alicyclic epoxy groups contained in1 molecule is 1, the number of ethylenically unsaturated groups contained in1 molecule is 1, and the molecular weight is 300 or less;

b) a radical polymerizable compound containing 3 or more ethylenically unsaturated groups in1 molecule;

c) a radical polymerization initiator; and

d) a cationic polymerization initiator. Hereinafter, this embodiment will be described as a second embodiment (2). The HC layer in which the curable composition for forming an HC layer according to the second embodiment (2) is cured preferably contains 15 to 70 mass% of the structure derived from the above a), 25 to 80 mass% of the structure derived from the above b), 0.1 to 10 mass% of the above c), and 0.1 to 10 mass% of the above d), assuming that the total solid content of the HC layer is 100 mass%. In one embodiment, the curable composition for forming an HC layer according to the second embodiment (2) preferably contains 15 to 70 mass% of the above-mentioned a) when the total solid content of the curable composition for forming an HC layer is 100 mass%. The "alicyclic epoxy group" refers to a 1-valent functional group having a cyclic structure of a fused epoxy ring and a saturated hydrocarbon ring.

Hereinafter, the respective components that can be contained in the curable composition for forming an HC layer of the second embodiment, preferably the second embodiment (1) or the second embodiment (2), will be described in further detail.

Radical polymerizable compound-

The curable composition for forming an HC layer according to the second embodiment contains at least one radical polymerizable compound and at least one cation polymerizable compound. The radical polymerizable compound in the second embodiment (1) contains 2 or more radical polymerizable groups selected from the group consisting of an acryloyl group and a methacryloyl group in1 molecule. The number of radical polymerizable groups selected from the group consisting of acryloyl and methacryloyl groups that can be contained in1 molecule of the radical polymerizable compound is preferably, for example, 2 to 10, and more preferably 2 to 6.

The radical polymerizable compound is preferably a radical polymerizable compound having a molecular weight of 200 or more and less than 1000. In the present invention and the present specification, the term "molecular weight" refers to a weight average molecular weight of a polymer measured in terms of polystyrene by Gel Permeation Chromatography (GPC). As an example of specific measurement conditions for the weight average molecular weight, the following measurement conditions can be cited.

GPC apparatus: HLC-8120(TOSOH CORPORATION)

Pipe column: TSKgelMultiporeHXL-M (manufactured by TOSOH CORPORATION, inner diameter 7.8 mm. times. length 30.0cm)

Eluent: tetrahydrofuran (THF)

The radical polymerizable compound preferably contains 1 or more urethane bonds in1 molecule as described above. The number of urethane bonds contained in1 molecule of the radical polymerizable compound is preferably 1 or more, more preferably 2 or more, and still more preferably 2 to 5, and for example, may be 2. In the radical polymerizable compound having 2 urethane bonds in1 molecule, the radical polymerizable group selected from the group consisting of an acryloyl group and a methacryloyl group may be bonded to only one of the urethane bonds directly or via a linking group, or may be bonded to 2 urethane bonds directly or via a linking group. In one embodiment, the 2 urethane bonds bonded via the linking group preferably bond 1 or more radical polymerizable groups selected from the group consisting of acryloyl and methacryloyl groups, respectively.

More specifically, in the radical polymerizable compound, the urethane bond may be directly bonded to a radical polymerizable group selected from the group consisting of an acryloyl group and a methacryloyl group, or a linking group may be present between the urethane bond and a radical polymerizable group selected from the group consisting of an acryloyl group and a methacryloyl group. The linking group is not particularly limited, and examples thereof include a linear or branched, saturated or unsaturated hydrocarbon group, a cyclic group, and a combination of 2 or more thereof. The number of carbon atoms of the hydrocarbon group is, for example, about 2 to 20, but is not particularly limited. Examples of the cyclic structure included in the cyclic group include an aliphatic ring (e.g., a cyclohexane ring), an aromatic ring (e.g., a benzene ring and a naphthalene ring), and the like. The above-mentioned group may be unsubstituted or substituted. In the present invention and the present specification, unless otherwise specified, the groups described may have a substituent or may be unsubstituted. When any group has a substituent, examples of the substituent include an alkyl group (e.g., an alkyl group having 1 to 6 carbon atoms), a hydroxyl group, an alkoxy group (e.g., an alkoxy group having 1 to 6 carbon atoms), a halogen atom (e.g., a fluorine atom, a chlorine atom, and a bromine atom), a cyano group, an amino group, a nitro group, an acyl group, and a carboxyl group.

The radical polymerizable compound described above can be synthesized by a known method. And also available as a commercially available product. For example, as an example of the synthesis method, there can be mentioned a method in which a hydroxyl group-containing compound such as an alcohol, a polyol and/or hydroxyl group-containing (meth) acrylic acid is reacted with an isocyanate or, if necessary, a polyurethane compound obtained by the above reaction is esterified with (meth) acrylic acid. In addition, "(meth) acrylic acid" means either one or both of acrylic acid and methacrylic acid.

Commercially available products of the radical polymerizable compound having 1 or more urethane bonds in the molecule of the above-mentioned 1 are not limited to those described below, but examples thereof include Kyoeisha Chemical Co., Ltd., UA-306H, UA-306I, UA-306T, UA-510H, UF-8001G, UA-101I, UA-101T, AT-600, AH-600, AI-600, BPZA-66, BPZA-100, Shin-Nakamura Chemical Co., Ltd., U-4HA, U-6LPA, UA-32P, U-15HA, UA-1100H, Nippon Synthetic Chemical Industry Co., Ltd., ultraviolet UV-1400B, ultraviolet UV-1700B, ultraviolet UV-6300B, ultraviolet UV-7550B, ultraviolet UV-7600B, and UV-767605B, Violet UV-7610B, violet UV-7620EA, violet UV-7630B, violet UV-7640B, violet UV-6630B, violet UV-7000B, violet UV-7510B, violet UV-7461TE, violet UV-3000B, violet UV-3200B, violet UV-3210EA, violet UV-3310B, violet UV-3500BA, violet UV-3520TL, violet UV-3700B, violet UV-6100B, violet UV-6640B, violet UV-2000B, violet UV-2010B, violet UV-2250 EA. Further, Nippon Synthetic chemical industry Co., Ltd, ultraviolet UV-2750B, Kyoeisha chemical Co., Ltd, UL-503LN Co., Ltd, Dainippon Ink and Chemicals, Unidic17-806, Unidic 17-813, Unidic V-4030, Unidic V-4000BA, Daicel-UCB Company, EB-1290 CO., Ltd, EB-1290K, TOKUSHIKI CO., Ltd, HaikopuAU-2010, Haikopu AU-2020, and the like can be cited.

Specific examples of the radical polymerizable compound containing 1 or more urethane bonds in1 molecule are shown below, but the present invention is not limited to the specific examples described below.

[ chemical formula 1]

[ chemical formula 2]

Although the radical polymerizable compound containing 1 or more urethane bonds in1 molecule has been described above, the radical polymerizable compound containing 2 or more radical polymerizable groups selected from the group consisting of an acryloyl group and a methacryloyl group in1 molecule may not have a urethane bond. The curable composition for forming an HC layer according to the second embodiment (1) may further contain one or more radical polymerizable compounds other than the radical polymerizable compound, in addition to the radical polymerizable compound containing 2 or more radical polymerizable groups selected from the group consisting of an acryloyl group and a methacryloyl group in1 molecule.

Hereinafter, a radical polymerizable compound containing 2 or more radical polymerizable groups selected from the group consisting of an acryloyl group and a methacryloyl group in1 molecule and containing 1 or more urethane bonds in1 molecule is referred to as a first radical polymerizable compound, and a radical polymerizable compound not suitable for the first radical polymerizable compound is referred to as a "second radical polymerizable compound" regardless of whether 2 or more radical polymerizable groups selected from the group consisting of an acryloyl group and a methacryloyl group are contained in1 molecule. The second radical polymerizable compound may or may not have 1 or more urethane bonds in1 molecule. When the first radically polymerizable compound and the second radically polymerizable compound are used in combination, the mass ratio is preferably 3/1 to 1/30, more preferably 2/1 to 1/20, and still more preferably 1/1 to 1/10.

The content of the radical polymerizable compound (irrespective of the presence or absence of a urethane bond) containing 2 or more radical polymerizable groups selected from the group consisting of an acryloyl group and a methacryloyl group in1 molecule in the curable composition for forming an HC layer according to the second embodiment (1) is preferably 30% by mass or more, more preferably 50% by mass or more, and still more preferably 70% by mass or more, relative to 100% by mass of the total composition. The content of the radical polymerizable compound (regardless of the presence or absence of a urethane bond) containing 2 or more radical polymerizable groups selected from the group consisting of an acryloyl group and a methacryloyl group in1 molecule in the curable composition for forming an HC layer according to the second embodiment (1) is preferably 98% by mass or less, more preferably 95% by mass or less, and still more preferably 90% by mass or less, relative to 100% by mass of the total composition.

The content of the first radically polymerizable compound in the curable composition for forming an HC layer according to the second embodiment (1) is preferably 30% by mass or more, more preferably 50% by mass or more, and still more preferably 70% by mass or more, based on 100% by mass of the total composition. On the other hand, the content of the first radically polymerizable compound is preferably 98% by mass or less, more preferably 95% by mass or less, and still more preferably 90% by mass or less, based on 100% by mass of the total composition.

In one embodiment, the second radical polymerizable compound is preferably a radical polymerizable compound having 2 or more radical polymerizable groups in1 molecule and having no urethane bond. The radical polymerizable group contained in the second radical polymerizable compound is preferably an ethylenically unsaturated group, and in one embodiment, is preferably a vinyl group. In another embodiment, the ethylenically unsaturated group is preferably a radical polymerizable group selected from the group consisting of an acryloyl group and a methacryloyl group. That is, the second radical polymerizable compound preferably has 1 or more radical polymerizable groups selected from the group consisting of an acryloyl group and a methacryloyl group in1 molecule and does not have a urethane bond. The second radical polymerizable compound may contain, in one molecule, 1 or more radical polymerizable groups selected from the group consisting of an acryloyl group and a methacryloyl group and 1 or more radical polymerizable groups other than these groups.

The number of radical polymerizable groups contained in1 molecule of the second radical polymerizable compound is preferably at least 2, more preferably 3 or more, and further preferably 4 or more. In one embodiment, the number of radical polymerizable groups contained in1 molecule of the second radical polymerizable compound is, for example, 10 or less, but may be more than 10. The second radical polymerizable compound is preferably a radical polymerizable compound having a molecular weight of 200 or more and less than 1000.

Examples of the second radical polymerizable compound include the following compounds. The present invention is not limited to the following exemplary compounds.

Examples thereof include polyethylene glycol 200 di (meth) acrylate, polyethylene glycol 300 di (meth) acrylate, polyethylene glycol 400 di (meth) acrylate, polyethylene glycol 600 di (meth) acrylate, triethylene glycol di (meth) acrylate, epichlorohydrin-modified Ethylene glycol di (meth) acrylate (commercially available products such as NAGASE & CO., DENACOLDA-811, manufactured by LTD., etc.), polypropylene glycol 200 di (meth) acrylate, polypropylene glycol 400 di (meth) acrylate, polypropylene glycol 700 di (meth) acrylate, Ethylene Oxide (EO; Ethylene Oxide). Propylene Oxide (PO; Propylene Oxide) block polyether di (meth) acrylate (commercially available products such as BLEMER PET series, manufactured by N.ippon Oil & Fats GmbH), dipropylene glycol di (meth) acrylate, bisphenol AEO addition type di (meth) acrylate (commercially available products, for example, TOAGO SEI CO., manufactured by LTD, M-210, Shin-Nakamura Chemical Co., manufactured by Ltd, NK ESTER A-BP E-20, manufactured by Ltd, hydrogenated bisphenol AEO addition type di (meth) acrylate (Shin-Nakamura Chemical Co., manufactured by Ltd, NKESTER A-HPE-4, manufactured by Ltd), bisphenol APO addition type di (meth) acrylate (commercially available, for example, Kyoeishacher Chemical Co., manufactured by Ltd, LIGHT ACRYLATE BP-4PA, manufactured by Ltd), bisphenol A epichlorohydrin addition type di (meth) acrylate (commercially available, for example, Daic el-UCB Company, EBECRYL 150, manufactured by Ltd), bisphenol AEO addition type di (meth) acrylate (commercially available, for example, Toho EI Co., manufactured by Ltd, BP-023-PE, etc.), and bisphenol AEO addition type di (meth) acrylate (commercially available, for example, AG CO., manufactured by AG), LTD. manufactured ARONIX M-208, etc.), 1, 6-hexanediol di (meth) acrylate and its epichlorohydrin-modified product, neopentyl glycol di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate and its caprolactone-modified product, 1, 4-butanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, trimethylolpropane di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, neopentyltetraol di (meth) acrylate monostearate, trimethylolpropane acrylate benzoate, isocyanurate EO-modified di (meth) acrylate (commercially available products, for example, TOAGOSEI CO., LTD. manufactured ARONIX M-215, etc.).

Also, there may be mentioned trimethylolpropane tri (meth) acrylate and EO, PO, epichlorohydrin-modified products thereof, pentaerythritol tri (meth) acrylate, glycerol tri (meth) acrylate and EO, PO, epichlorohydrin-modified products thereof, isocyanurate EO-modified tri (meth) acrylate (commercially available products such as TOAGOSEI CO., LTD. ARONIX M-315, etc.), tri (meth) acryloyloxyethyl ester, hydrogen phthalate- (2, 2, 2-tri- (meth) acryloyloxymethyl) ethyl ester, glycerol tri (meth) acrylate and 3-functional (meth) acrylate compounds such as EO, PO, epichlorohydrin-modified products thereof, etc.; 4-functional (meth) acrylate compounds such as neopentyltetraol tetra (meth) acrylate, EO, PO, epichlorohydrin-modified products thereof, ditrimethylolpropane tetra (meth) acrylate, and the like; 5-functional (meth) acrylate compounds such as dipentaerythritol penta (meth) acrylate and EO, PO, epichlorohydrin, fatty acid, and alkyl-modified products thereof; dipentaerythritol hexa (meth) acrylate and its 6-functional (meth) acrylates such as EO, PO, epichlorohydrin, fatty acid, alkyl-modified products, sorbitol hexa (meth) acrylate and its EO, PO, epichlorohydrin, fatty acid, alkyl-modified products, etc.

The second radical polymerizable compound may be used in combination of 2 or more. In this case, a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate, "DPHA" (manufactured by Nippon Kayaku co., ltd.) or the like can be preferably used.

Further, as the second radical polymerizable compound, polyester (meth) acrylate and epoxy (meth) acrylate having a weight average molecular weight of 200 or more and less than 1000 are also preferable. Examples of commercially available polyester (meth) acrylates include ARAKAWA CHEMICAL INDUSTRIES, Ltd, product name BEAMSET 700 series, for example BEAMSET 700 (6-functional), BEAMSE T710 (4-functional), BEAMSET 720 (3-functional), and the like. Examples of the epoxy (meth) acrylate include SP series products manufactured by Showa Highpolymer Co., Ltd, such as SP-1506, 500, SP-1507, 480, VR series products, such as VR-77, Shin-Nakamura Chemical Co., Ltd, EA-1010/ECA, EA-11020, EA-1025, EA-6310/ECA products manufactured by Ltd.

Specific examples of the second radical polymerizable compound include the following compounds.

[ chemical formula 3]

The curable composition for forming an HC layer according to a preferred embodiment of the second embodiment, that is, according to the second embodiment (2), contains b) a radical polymerizable compound containing 3 or more ethylenically unsaturated groups in1 molecule. Hereinafter, the compound b) containing 3 or more ethylenically unsaturated groups in1 molecule is referred to as "component b").

Examples of the component b) include esters of polyhydric alcohols and (meth) acrylic acid, vinylbenzenes and derivatives thereof, vinyl sulfones, and (meth) acrylamides. Among them, a radical polymerizable compound containing 3 or more radical polymerizable groups selected from the group consisting of acryloyl groups and methacryloyl groups in1 molecule is preferable. Specific examples thereof include esters of polyhydric alcohols and (meth) acrylic acid, and compounds having 3 or more ethylenically unsaturated groups in1 molecule. More specifically, examples thereof include (di) neopentyltetraol tetra (meth) acrylate, (di) neopentyltetraol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO-modified phosphoric acid tri (meth) acrylate, trimethylolethane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, (di) neopentyltetraol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, neopentyltetraol hexa (meth) acrylate, 1, 2, 3-cyclohexane tetramethylacrylate, polyamine ester polyacrylate, polyester polyacrylate, caprolactone-modified tri (acryloyloxyethyl) isocyanurate, Trineopentyltetraol triacrylate, trineopentyltetraol hexatriacrylate, 1, 2, 4-cyclohexanetetra (meth) acrylate, pentaglycerol triacrylate, and the like. The "(di) neopentyltetraol" is used as meaning 1 or both of neopentyltetraol and dipentaerythritol.

Further, a resin containing 3 or more radical polymerizable groups selected from the group consisting of acryloyl groups and methacryloyl groups in1 molecule is also preferable.

Examples of the resin containing 3 or more radical polymerizable groups selected from the group consisting of an acryloyl group and a methacryloyl group in1 molecule include polymers of polyfunctional compounds such as polyester resins, polyether resins, acrylic resins, epoxy resins, polyurethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polymercapto-polyolefin resins, and polyols.

Specific examples of the radical polymerizable compound containing 3 or more radical polymerizable groups selected from the group consisting of an acryloyl group and a methacryloyl group in1 molecule include compounds exemplified in paragraph 0096 of jp 2007-a 256844, and the like.

Specific examples of the radical polymerizable compound containing 3 or more radical polymerizable groups selected from the group consisting of acryloyl groups and methacryloyl groups in1 molecule include esterified products of a (meth) acrylic acid with a polyhydric alcohol such as Nippon Kayaku Co., Ltd, KAYARADDPHA, KAYARAD DPHA-2C, KAYARAD PET-30, KAYARAD TMPTA, KAYARAD TPA-320, KAYARAD TPA-330, KAYARAD RP-1040, KAYARAD T-1420, KAYARAD D-310, KAYARAD DPCA-20, KAYARAD DPCA-30, KAYARAD DPCA-60, KAYARAD GPO-303, OSAKA ORGANIC CHEMICALLINDURY LTD., V #400, V # 36095D. Further, preferably, violet UV-1400B, violet UV-1700B, violet UV-6300B, violet UV-7550B, violet UV-7600B, violet UV-7605B, violet UV-7610B, violet UV-7620EA, violet UV-7630B, violet UV-7640B, violet UV-6630B, violet UV-7000B, violet UV-7510B, violet UV-7461T E, violet UV-3000B, violet UV-3200B, violet UV-3210EA, violet UV-3310B, violet UV-3500BA, violet UV-3520TL, violet UV-3700B, violet UV-6100B, violet UV-6640B, violet UV-2000B, violet UV-2010B, violet UV-350 TL, Synthetic UV-270B (Synthetic Co., Chemical Co., industrial, ltd.), UL-503LN (Kyoeisha chemical Co., Ltd.), UNIDIC17-806, UNIDIC 17-813, UNIDIC V-4030, UNIDIC V-4000BA (manufactured by Dainippon Ink and Chemicals, Inc.), EB-1290K, EB-220, EB-5129, EB-1830, EB-4358(Daicel-UCB company, manufactured by Ltd.), Haikopu AU-2010, Haikopu AU-2020 ((manufactured by Tokushi Kico., manufactured by Ltd.), ARONIX M-1960(TOAGOSEI CO., manufactured by LTD.), ArtResin UN-3320HA, UN-3320HC, UN-3320HS, UN-904, HDP-4T, and the like, and ARONIX M-8100, M-8030, M-9050(TOAGOSEI CO., manufactured by LTD.), KBM-8307(DAICEL-ALLNEX LTD., manufactured by LTD., and the like.

The component b) may be used alone or in combination of two or more different structures.

As described above, the HC layer in which the curable composition for forming an HC layer according to the second embodiment (2) is cured preferably can include 15 to 70 mass% of the structure derived from the above a), 25 to 80 mass% of the structure derived from the above b), 0.1 to 10 mass% of the above c), and 0.1 to 10 mass% of the above d), assuming that the total solid content of the HC layer is 100 mass%. The structure derived from b) is preferably contained in an amount of 40 to 75% by mass, more preferably 60 to 75% by mass, based on 100% by mass of the total solid content of the HC layer. The curable composition for forming an HC layer according to the second embodiment (2) preferably contains 40 to 75 mass%, more preferably 60 to 75 mass%, of the component b) when the total solid content of the curable composition for forming an HC layer is 100 mass%.

Cationic polymerizable compound

The curable composition for forming an HC layer according to the second embodiment preferably contains at least one radical polymerizable compound and at least one cation polymerizable compound. The cationically polymerizable compound can be used without any limitation as long as it has a polymerizable group (cationically polymerizable group) capable of polymerizing cations. The number of the cationically polymerizable groups contained in1 molecule is at least 1. The cationically polymerizable compound may be a monofunctional compound containing 1 cationically polymerizable group in1 molecule, or may contain 2 or more functional compounds. The number of the cationically polymerizable groups contained in the polyfunctional compound is not particularly limited, but is, for example, 2 to 6 in1 molecule. The polyfunctional compound may have 2 or more cationically polymerizable groups in1 molecule, and may have the same structure or two or more species having different structures.

In one embodiment, the cationically polymerizable compound preferably further has a cationically polymerizable group and 1 or more radically polymerizable groups in1 molecule. As for the radical polymerizable group of the cation polymerizable compound, the above description of the radical polymerizable compound can be referred to. The ethylenically unsaturated group is preferably an ethylenically unsaturated group, and the ethylenically unsaturated group is more preferably a radical polymerizable group selected from the group consisting of a vinyl group, an acryloyl group and a methacryloyl group. The number of radical polymerizable groups in1 molecule of the cation polymerizable compound having a radical polymerizable group is at least 1, preferably 1 to 3, and more preferably 1.

Preferable examples of the cationically polymerizable group include an oxygen-containing heterocyclic group and a vinyl ether group. The cationically polymerizable compound may contain 1 or more oxygen-containing heterocyclic groups and 1 or more vinyl ether groups in1 molecule.

The oxygen-containing heterocycle may be a monocyclic ring or a condensed ring. Also, a bicyclic skeleton is preferable. The oxygen-containing heterocyclic ring may be a non-aromatic ring or an aromatic ring, and is preferably a non-aromatic ring. Specific examples of the monocyclic ring include an epoxy ring, a tetrahydrofuran ring and an oxetane ring. The bicyclic skeleton may be an oxabicyclo skeleton. The cation polymerizable compound contains an oxygen-containing heterocyclic ring as a substituent having a valence of 1 or a polyvalent substituent having a valence of 2 or more. The fused ring may be fused with 2 or more oxygen-containing heterocyclic rings, or may be fused with 1 or more oxygen-containing heterocyclic rings and 1 or more ring structures other than the oxygen-containing heterocyclic rings. The ring structure other than the oxygen-containing heterocyclic ring is not limited to the above, but a cycloalkane ring such as a cyclohexane ring can be mentioned.

Specific examples of the oxygen-containing heterocyclic ring are shown below. However, the present invention is not limited to the following specific examples.

[ chemical formula 4]

The cationically polymerizable compound may contain a partial structure other than the cationically polymerizable group. The partial structure is not particularly limited, and may be a linear structure, a branched structure, or a cyclic structure. These partial structures may contain 1 or more heteroatoms such as oxygen atom and nitrogen atom.

A preferable embodiment of the cationically polymerizable compound includes a compound (cyclic structure-containing compound) having a cyclic structure as a cationically polymerizable group or as a partial structure other than the cationically polymerizable group. The number of cyclic structures contained in the cyclic structure-containing compound may be, for example, 1, or 2 or more per 1 molecule. The number of cyclic structures contained in the cyclic structure-containing compound is, for example, 1 to 5 in1 molecule, but is not particularly limited. The compound containing 2 or more cyclic structures in1 molecule may contain the same cyclic structure, or may contain two or more cyclic structures having different structures.

An example of the cyclic structure contained in the cyclic structure-containing compound is an oxygen-containing heterocycle. The details thereof are as described above.

The cation polymerizable group equivalent weight (═ B/C) obtained by dividing the molecular weight (hereinafter referred to as "B") by the number of cation polymerizable groups contained in1 molecule of the cation polymerizable compound (hereinafter referred to as "C") is, for example, 300 or less, and is preferably less than 150 from the viewpoint of improving the adhesion between the HC layer and the resin film in which the curable composition for forming an HC layer is cured. On the other hand, the cation polymerizable group equivalent weight is preferably 50 or more from the viewpoint of the moisture absorption of the HC layer in which the curable composition for forming an HC layer is cured. In one embodiment, the cationically polymerizable group contained in the cationically polymerizable compound whose equivalent weight is determined may be an epoxy group (epoxy ring). That is, in one embodiment, the cationically polymerizable compound is an epoxy ring-containing compound. From the viewpoint of improving the adhesion between the HC layer obtained by curing the curable composition for forming an HC layer and the resin film, the epoxy group equivalent weight of the epoxy ring-containing compound determined by dividing the molecular weight by the number of epoxy rings contained in1 molecule is preferably less than 150. The epoxy equivalent of the epoxy ring-containing compound is, for example, 50 or more.

The molecular weight of the cationically polymerizable compound is preferably 500 or less, and more preferably 300 or less. It is presumed that the cationically polymerizable compound having a molecular weight in the above range tends to easily permeate into the resin film, and can contribute to improvement of adhesion between the HC layer and the resin film in which the curable composition for forming an HC layer is cured.

The curable composition for forming an HC layer according to the second embodiment (2) contains a cationically polymerizable compound containing a) an alicyclic epoxy group and an ethylenically unsaturated group, the number of alicyclic epoxy groups contained in1 molecule being 1, and the number of ethylenically unsaturated groups contained in1 molecule being 1, and the molecular weight being 300 or less. Hereinafter, the above-mentioned a) is referred to as "a) component".

Examples of the ethylenically unsaturated group include radical polymerizable groups containing an acryloyl group, a methacryloyl group, a vinyl group, a styryl group, an allyl group, and the like, and among them, an acryloyl group, a methacryloyl group, and c (o) OCH ═ CH are preferable₂More preferred are acryloyl and methacryloyl. The number of the alicyclic epoxy group and the ethylenically unsaturated group in1 molecule is preferably 1.

a) The molecular weight of the component (B) is 300 or less, preferably 210 or less, more preferably 200 or less.

A preferable embodiment of the component a) is a compound represented by the following general formula (1).

[ chemical formula 5]

In the general formula (1), R represents a monocyclic hydrocarbon or a crosslinked hydrocarbon, L represents a single bond or a 2-valent linking group, and Q represents an ethylenically unsaturated group.

When R in the formula (1) is a monocyclic hydrocarbon, it is preferably a monocyclic hydrocarbon alicyclic hydrocarbon, more preferably an alicyclic group having 4 to 10 carbon atoms, still more preferably an alicyclic group having 5 to 7 carbon atoms, and particularly preferably an alicyclic group having 6 carbon atoms. Preferable specific examples thereof include cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl, and cyclohexyl is more preferable.

When R in the general formula (1) is a crosslinking hydrocarbon, the crosslinking hydrocarbon is preferably a 2-ring system crosslinking hydrocarbon (bicyclic ring) or a 3-ring system crosslinking hydrocarbon (tricyclic ring). Specific examples thereof include crosslinked hydrocarbons having 5 to 20 carbon atoms, for example, norbornyl, camphyl, isoborneyl, tricyclodecyl, dicyclopentenyl, tricyclopentenyl, adamantyl, lower (for example, having 1 to 6 carbon atoms) alkyl-substituted adamantyl, and the like.

When L represents a linking group having a valence of 2, the linking group having a valence of 2 is preferably an aliphatic hydrocarbon group having a valence of 2. The number of carbon atoms of the 2-valent aliphatic hydrocarbon group is preferably in the range of 1 to 6, more preferably in the range of 1 to 3, and even more preferably 1. The aliphatic hydrocarbon group having a valence of 2 is preferably a linear, branched or cyclic alkylene group, more preferably a linear or branched alkylene group, and still more preferably a linear alkylene group.

Examples of Q include ethylenically unsaturated groups containing an acryloyl group, methacryloyl group, vinyl group, styryl group, allyl group, and the like, and among these, acryloyl group, methacryloyl group, and c (o) OCH ═ CH are preferable₂More preferred are acryloyl and methacryloyl.

Specific examples of the component a) include various compounds exemplified in paragraph 0015 of Japanese patent application laid-open No. 10-017614, compounds represented by the following general formula (1A) or (1B), 1, 2-epoxy-4-vinylcyclohexane, and the like. Among them, a compound represented by the following general formula (1A) or (1B) is more preferable. Further, it is also preferable that the compound represented by the following general formula (1A) is an isomer thereof.

[ chemical formula 6]

[ chemical formula 7]

In the general formulae (1A) and (1B), R₁Represents a hydrogen atom or a methyl group, L₂Represents a C1-6 aliphatic hydrocarbon group with a valence of 2.

From L in the general formulae (1A) and (1B)₂The number of carbon atoms of the 2-valent aliphatic hydrocarbon group is in the range of 1 to 6, more preferably in the range of 1 to 3, and still more preferably 1. The aliphatic hydrocarbon group having a valence of 2 is preferably a linear, branched or cyclic alkylene group, more preferably a linear or branched alkylene group, and still more preferably a linear alkylene group.

The HC layer in which the curable composition for forming an HC layer is cured according to the second embodiment (2) preferably contains 15 to 70% by mass, more preferably 18 to 50% by mass, and still more preferably 22 to 40% by mass of the structure derived from the above a) when the total solid content of the HC layer is 100% by mass. In the curable composition for forming an HC layer according to the second embodiment (2), when the total solid content of the curable composition for forming an HC layer is 100 mass%, the component a) is preferably contained in an amount of 15 to 70 mass%, more preferably 18 to 50 mass%, and still more preferably 22 to 40 mass%.

As another example of the cyclic structure included in the above-mentioned compound having a cyclic structure, a nitrogen-containing heterocycle can be given. The compound containing a nitrogen-containing heterocycle is preferably a cationically polymerizable compound from the viewpoint of improving adhesion between the HC layer and the resin film in which the curable composition for forming an HC layer is cured. The nitrogen-containing heterocyclic ring-containing compound is preferably a compound having 1 or more nitrogen-containing heterocyclic rings selected from the group consisting of a isocyanurate ring and a thiourea ring in1 molecule. Among these, from the viewpoint of improving the adhesion between the HC layer obtained by curing the curable composition for forming an HC layer and the resin film, it is more preferable that the compound containing a trimeric isocyanate ring (trimeric isocyanate ring-containing compound) is a cationically polymerizable compound. The present inventors speculate that this is because the affinity of the polyisocyanurate ring with the resin constituting the resin film is excellent. From this viewpoint, a resin film containing an acrylic resin film is more preferable, and the surface in direct contact with the HC layer in which the curable composition for forming an HC layer is cured is more preferably the surface of the acrylic resin film.

In addition, another example of the cyclic structure included in the cyclic structure-containing compound is an alicyclic structure. Examples of the alicyclic structure include monocyclic, bicyclic, and tricyclic structures, and specific examples thereof include dicyclopentyl ring and cyclohexane ring.

The cationic polymerizable compound described above can be synthesized by a known method. And, it can also be obtained as a commercially available product.

Specific examples of the cationically polymerizable compound containing an oxygen-containing heterocycle as a cationically polymerizable group include 3, 4-epoxycyclohexylmethyl methacrylate (commercially available products such as Daicel Corporation Co., Ltd., CYCLOMER M100 manufactured by Ltd.), 3, 4-epoxycyclohexylmethyl-3 ', 4' -epoxycyclohexanecarboxylate (commercially available products such as UVR6105, UVR6110 and Daicel Corporation Co., Ltd., CELLOXIDE2021 manufactured by Ltd.), bis (3, 4-epoxycyclohexylmethyl) adipate (e.g., R6128 manufactured by Union Carbide Corporation), vinylcyclohexene monoepoxide (e.g., Daicel Corporation Co., Ltd., CELLOXIDE2000 manufactured by Ltd Corporation), ε -caprolactone 3, 4-epoxycyclohexylmethyl 3 ', 4' -epoxycyclohexanecarboxylate (e.g., Daicel Co., Ltd., LOXIDE 1 manufactured by Ltd Corporation), LOmethyl-2081- (methyl-ethyl) -4- (epoxy-bicyclo [ 4-ethyl ] 2087-ethyl-4-methyl-epoxy), 1, 0] heptane (e.g., Daicel Corporation Co., Ltd. CELLOXIDE3000), 7 '-dioxo-3, 3' -bis [ bicyclo [4.1.0] heptane ] (e.g., Daicel Corporation Co., Ltd. CELLOXIDE8000), 3-ethyl-3-hydroxymethoxyoxetane, 1, 4 bis { [ (3-ethyl-3-oxetanyl) methoxy ] methyl } benzene, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, and bis [ 1-ethyl (3-oxetanyl) ] methyl ether, etc.

Specific examples of the cationically polymerizable compound containing a vinyl ether group as a cationically polymerizable group include 1, 4-butanediol divinyl ether, 1, 6-hexanediol divinyl ether, nonanediol divinyl ether, cyclohexanediol divinyl ether, cyclohexanedimethanol divinyl ether, triethylene glycol divinyl ether, trimethylolpropane trivinyl ether, neopentyltetraol tetraethylene ether, and the like. The cationically polymerizable compound containing a vinyl ether group also preferably has an alicyclic structure.

Further, as the cation polymerizable compound, compounds exemplified in Japanese patent application laid-open Nos. 8-143806, 8-283320, 2000-186079, 2000-327672, 2004-315778, 2005-029632 and the like can be used.

Hereinafter, the compound will be described as an example of the cationically polymerizable compound, but the present invention is not limited to the following example.

[ chemical formula 8]

[ chemical formula 9]

[ chemical formula 10]

In addition, from the viewpoint of improving the adhesion between the HC layer in which the curable composition for forming an HC layer is cured and the resin film, the following embodiments can be cited as preferred embodiments of the curable composition for forming an HC layer. More preferably 1 or more, still more preferably 2 or more, still more preferably 3 or more, and still more preferably all of the following embodiments are satisfied. In addition, 1 cationically polymerizable compound also preferably satisfies a plurality of embodiments. For example, a preferable embodiment can be exemplified by a case where the nitrogen-containing heterocyclic ring-containing compound is less than 150 cation polymerizable group equivalent.

(1) The cationically polymerizable compound includes a compound containing a nitrogen-containing heterocycle. The nitrogen-containing heterocyclic ring of the nitrogen-containing heterocyclic ring-containing compound is preferably selected from the group consisting of a isocyanurate ring and a thiourea ring. The nitrogen-containing heterocyclic ring-containing compound is more preferably a trimeric isocyanate ring-containing compound. The isocyanurate ring-containing compound is preferably an epoxy ring-containing compound containing 1 or more epoxy rings in1 molecule.

(2) The cationically polymerizable compound includes a cationically polymerizable compound having a cationically polymerizable group equivalent of less than 150. Preferably an epoxy group-containing compound having an epoxy equivalent of less than 150.

(3) The cationically polymerizable compound contains an ethylenically unsaturated group.

(4) The cationically polymerizable compound includes an oxetane ring-containing compound containing 1 or more oxetane rings in1 molecule together with other cationically polymerizable compounds. The oxetane ring-containing compound is preferably a compound containing no nitrogen-containing heterocycle.

The content of the cationically polymerizable compound in the curable composition for forming an HC layer is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and still more preferably 20 parts by mass or more, based on 100 parts by mass of the total content of the radically polymerizable compound and the cationically polymerizable compound. The content of the cationically polymerizable compound in the curable composition for forming an HC layer is preferably 50 parts by mass or less based on 100 parts by mass of the total content of the radically polymerizable compound and the cationically polymerizable compound.

The content of the cationically polymerizable compound in the curable composition for forming an HC layer is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and still more preferably 1 part by mass or more, based on 100 parts by mass of the total content of the first radically polymerizable compound and the cationically polymerizable compound. On the other hand, the content of the cationically polymerizable compound is preferably 50 parts by mass or less, and more preferably 40 parts by mass or less, based on 100 parts by mass of the total content of the first radically polymerizable compound and the cationically polymerizable compound.

In the present invention and the present specification, the compound having a cationically polymerizable group and a radically polymerizable group is classified into a cationically polymerizable compound, and the content of the compound in the curable composition for forming an HC layer is defined.

Polymerization initiators

The curable composition for forming an HC layer preferably contains a polymerization initiator, and more preferably contains a photopolymerization initiator. The curable composition for forming an HC layer containing a radical polymerizable compound preferably contains a radical photopolymerization initiator, and the curable composition for forming an HC layer containing a cation polymerizable compound preferably contains a cation photopolymerization initiator. The radical photopolymerization initiator or the cationic polymerization initiator may be used alone, or two or more kinds of initiators having different structures may be used in combination.

The content of the polymerization initiator in the curable composition for forming an HC layer may be appropriately adjusted within a range in which the polymerization reaction of the polymerizable compound is favorably carried out, and is not particularly limited. The amount of the polymerizable compound is, for example, 0.1 to 20 parts by mass, preferably 0.5 to 10 parts by mass, and more preferably 1 to 10 parts by mass, based on 100 parts by mass of the polymerizable compound contained in the curable composition for forming an HC layer.

A component optionally contained in the curable composition for forming an HC layer

The curable composition for forming an HC layer contains at least one component having a property of being cured by irradiation with active energy rays, and may optionally contain at least one polymerization initiator, and preferably contains the same. These details are as described previously.

Next, various components that can be optionally contained in the curable composition for forming an HC layer will be described.

(i) Inorganic particles

The curable composition for forming an HC layer can contain inorganic particles having an average primary particle diameter of less than 2 μm. The average primary particle diameter of the inorganic particles is preferably in the range of 10nm to 1 μm, more preferably in the range of 10nm to 100nm, and still more preferably in the range of 10nm to 50 nm.

The average primary particle diameters of the inorganic particles and the matting particles described later were observed by a transmission electron microscope (magnification: 50 to 200 ten thousand times), 100 randomly selected particles (primary particles) were observed, and the average of these particle diameters was defined as the average primary particle diameter.

Examples of the inorganic particles include silica particles, titania particles, zirconia particles, and alumina particles. Among them, silica particles are preferable.

In order to improve the affinity with the organic component contained in the curable composition for forming an HC layer, the inorganic particles may be treated with a surface modifier having an organic segment on the surface thereof. The surface modifier preferably has, in the same molecule, a functional group that forms a bond with the inorganic particle or can be adsorbed to the inorganic particle and a functional group that has high affinity for the organic component. The surface modifier having a functional group capable of being bonded to or adsorbed on the inorganic particles is preferably a silane-based surface modifier, a metal alkoxide surface modifier such as aluminum, titanium, or zirconium, or a surface modifier having an anionic group such as a phosphoric group, a sulfuric group, a sulfonic group, or a carboxylic group. Examples of the functional group having high affinity with the organic component include a functional group having the same hydrophilicity and hydrophobicity as the organic component, a functional group capable of chemically bonding with the organic component, and the like. Among these, a functional group or the like capable of chemically bonding to an organic component is preferable, and an ethylenically unsaturated group or a ring-opening polymerizable group is more preferable.

The inorganic particle surface modifier is preferably a metal alkoxide surface modifier or a polymerizable compound having an anionic group and an ethylenically unsaturated group or a ring-opening polymerizable group in the same molecule. The inorganic particles and the organic component are chemically bonded by the surface modifier, whereby the crosslinking density of the HC layer can be increased, and as a result, the hardness of the front panel (including the hardness of the liquid crystal panel of the front panel) can be increased.

Specific examples of the surface modifier include the following compounds S-1 to S-8.

S-1 H₂C＝C(X)COOC₃H₆Si(OCH₃)₃

S-2 H₂C＝C(X)COOC₂H₄OTi(OC₂H₅)₃

S-3 H₂C＝C(X)COOC₂H₄OCOC₅H₁₀OPO(OH)₂

S-4(H₂C＝C(X)COOC₂H₄OCOC₅H₁₀O)₂POOH

S-5 H₂C＝C(X)COOC₂H₄OSO₃H

S-6 H₂C＝C(X)COO(C₅H₁₀COO)₂H

S-7 H₂C＝C(X)COOC₅H₁₀COOH

S-8 CH₂CH(O)CH₂OC₃H₆Si(OCH₃)₃

(X represents a hydrogen atom or a methyl group)

The surface modification of the inorganic particles based on the surface modifier is preferably carried out in solution. In the case of mechanically dispersing the inorganic particles, the surface modifier may be present together with the inorganic particles, or the inorganic particles may be mechanically dispersed, followed by adding the surface modifier and stirring, or the inorganic particles may be mechanically dispersed, followed by surface modification (heating, drying, heating, or ph (power of hydrogen) change, if necessary) before the surface modifier is added and stirred, or the inorganic particles may be mechanically dispersed. The solvent for dissolving the surface modifier is preferably an organic solvent having a large polarity. Specifically, known solvents such as alcohols, ketones, and esters can be mentioned.

The content of the inorganic particles is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on 100% by mass of the total solid content of the curable composition for forming an HC layer. The shape of the primary particles of the inorganic particles may be spherical or non-spherical, but the primary particles of the inorganic particles are preferably spherical, and from the viewpoint of further improving the hardness, the primary particles of the inorganic particles are more preferably present as high-order particles of 2 or more non-spherical primary particles to which 2 to 10 spherical inorganic particles (primary particles) are connected in the HC layer in which the curable composition for forming an HC layer is cured.

Specific examples of the inorganic particles include ELCOM V-8802 (spherical silica particles having an average primary particle diameter of 15nm manufactured by JGC Catalysts and Chemicals Ltd.), ELCOM V-8803 (shaped silica particles manufactured by JGCCatalysts and Chemicals Ltd.), MiBK-SD (spherical silica particles having an average primary particle diameter of 10 to 20nm manufactured by Nissan chemical Industries, LTD.), MEK-AC-2140Z (spherical silica particles having an average primary particle diameter of 10 to 20nm manufactured by Nissan chemical Industries, LTD.), MEK-AC-4130 (spherical silica particles having an average primary particle diameter of 45nm manufactured by Nissan Chemical Industries, LTD.), MiBK-SD-L (spherical silica particles having an average primary particle diameter of 40 to 50nm manufactured by Nissan Chemical Industries, LTD.), MEK-AC-5140Z (spherical silica particles having an average primary particle diameter of 85nm manufactured by Nissan Chemical Industries, LTD.), and the like. Among them, ELCOM V-8802 made by JGC C catalysts and Chemicals Ltd. is preferable from the viewpoint of further improving hardness.

(ii) Matting particles

The curable composition for forming an HC layer may contain matting particles. The matte particles are particles having an average primary particle diameter of 2 μm or more, and may be inorganic particles, organic particles, or particles of inorganic and organic composite materials. The shape of the matting particles may be spherical or non-spherical. The average primary particle diameter of the matting particles is preferably in the range of 2 to 20 μm, more preferably in the range of 4 to 14 μm, and still more preferably in the range of 6 to 10 μm.

Specific examples of the matting particles include silica particles and TiO₂Inorganic particles such as particles, crosslinked acrylic acid-styrene particles, crosslinked styrene particles, melamine resin particles, benzoguanamine resin particles, and the likeOrganic particles. Among them, the matte particles are preferably organic particles, and more preferably crosslinked acrylic acid particles, crosslinked acrylic acid-styrene particles, and crosslinked styrene particles.

The content of the matte particles per unit volume in the HC layer of the curable composition for forming the HC layer is preferably 0.10g/cm³Above, more preferably 0.10g/cm³～0.40g/cm³More preferably 0.10g/cm³～0.30g/cm³。

(iii) Ultraviolet absorber

The curable composition for forming an HC layer also preferably contains an ultraviolet absorber. Examples of the ultraviolet absorber include benzotriazole compounds and triazine compounds. Among them, the benzotriazole compound is a compound having a benzotriazole ring, and specific examples thereof include various benzotriazole-based ultraviolet absorbers described in the paragraph 0033 of Japanese patent laid-open publication No. 2013-111835. The triazine compound is a compound having a triazine ring, and specific examples thereof include various triazine-based ultraviolet absorbers described in jp 2013-111835 a 0033. The content of the ultraviolet absorber in the HC layer is, for example, about 0.1 to 10 parts by mass with respect to 100 parts by mass of the resin contained in the HC layer, but is not particularly limited. Further, as for the ultraviolet absorber, reference can also be made to paragraph 0032 of Japanese patent laid-open publication No. 2013-111835. In the present invention and the specification, the ultraviolet ray refers to light having an emission center wavelength in a wavelength band of 200 to 380 nm.

(iv) Fluorine-containing compound

The curable composition for forming an HC layer preferably contains a fluorine-containing compound such as a leveling agent and an antifouling agent.

As leveling agent, fluoropolymers are preferably used. Examples thereof include the fluoroaliphatic group-containing polymers described in Japanese patent No. 5175831. Further, a fluoroaliphatic group-containing polymer in which the content of the fluoroaliphatic group-containing monomer represented by the general formula (1) constituting the fluoroaliphatic group-containing polymer is 50 mass% or less of the total polymerized units can be used as the leveling agent.

If the HC layer contains an antifouling agent, the adhesion of fingerprints or stains is reduced, and the adhered stains can be easily wiped off. Further, by improving the lubricity of the surface, the abrasion resistance can be further improved.

The antifouling agent preferably contains a fluorine-containing compound. The fluorine-containing compound preferably has a perfluoropolyether group and a polymerizable group (preferably a radical polymerizable group), and more preferably has a perfluoropolyether group and a polymerizable group and has a plurality of polymerizable groups in one molecule. With such a configuration, the effect of improving the abrasion resistance can be more effectively exhibited.

In the present specification, even when the antifouling agent has a polymerizable group, the treatment is not performed on the polymerizable compound 1 to 3 and the other polymerizable compound.

The fluorine-containing compound may be any of a monomer, an oligomer, and a polymer, but is preferably an oligomer (fluorine-containing oligomer).

In addition to the above, other leveling agents and antifouling agents described in (vi) below may be contained.

The antifouling agent that can be used in the present invention may be any of the antifouling agents described in paragraphs 0012 to 0101 of Japanese patent application laid-open No. 2012-088699, the contents of which are incorporated herein.

As the antifouling agent described above, an antifouling agent synthesized by a known method may be used, or a commercially available product may be used. As commercially available products, RS-90, RS-78, etc. manufactured by DIC Corporation can be preferably used.

When the curable composition for forming an HC layer contains a fluorine-containing compound, the content thereof is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and still more preferably 0.1 to 2% by mass of the solid content of the curable composition for forming an HC layer.

The curable composition for forming an HC layer may contain only 1 kind of antifouling agent, or may contain 2 or more kinds. When 2 or more species are contained, the total amount thereof is preferably within the above range.

The curable composition for forming an HC layer may have a structure that does not substantially contain an antifouling agent.

(v) Solvent(s)

The curable composition for forming an HC layer also preferably contains a solvent. The solvent is preferably an organic solvent, and 1 or 2 or more kinds of organic solvents can be mixed at an arbitrary ratio and used. Specific examples of the organic solvent include alcohols such as methanol, ethanol, propanol, n-butanol and isobutanol; ketones such as acetone, methyl isobutyl ketone, methyl ethyl ketone, and cyclohexanone; cellosolves such as ethyl cellosolve; aromatic compounds such as toluene and xylene; glycol ethers such as propylene glycol monomethyl ether; acetates such as methyl acetate, ethyl acetate, and butyl acetate; diacetone alcohol, and the like. Of these, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone and methyl acetate are preferable, and cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone and methyl acetate are more preferably mixed in an arbitrary ratio and used. With such a structure, an antireflection laminate having further excellent abrasion resistance, punching properties, and adhesion can be obtained.

The amount of the solvent in the curable composition for forming an HC layer can be appropriately adjusted within a range that ensures the applicability of the composition. For example, the solvent may be 50 to 500 parts by mass, preferably 80 to 200 parts by mass, based on 100 parts by mass of the total amount of the polymerizable compound and the photopolymerization initiator.

The solid content of the curable composition for forming HC is preferably 10 to 90% by mass, more preferably 50 to 80% by mass, and particularly preferably 65 to 75% by mass.

(vi) Other ingredients

The curable composition for forming an HC layer may contain one or more known additives in an arbitrary amount in addition to the above components. Examples of the additives include surface conditioners, leveling agents, polymerization inhibitors, and polyrotaxanes. For details, for example, refer to paragraphs 0032 to 0034 of Japanese patent laid-open No. 2012 and 229412. Further, a commercially available antifouling agent or an antifouling agent prepared by a known method may be contained. The additive is not limited to these, and various additives usually added to the curable composition for forming an HC layer can be used.

The curable composition for forming an HC layer can be prepared by mixing the above-described components in sequence at the same time or in any order. The preparation method is not particularly limited, and a known stirrer or the like can be used for the preparation.

2) Laminated structure with more than 2 layers

In the laminate, the HC layer 1A in fig. 1 preferably has at least a 1 st HC layer and a2 nd HC layer in the order of the resin film 2A.

The 1 st HC layer may be provided on the surface of the resin film 2A, or another layer may be provided therebetween. Similarly, the 1 st HC layer may have the 2 nd HC layer on the surface thereof, and may have other layers therebetween. From the viewpoint of improving the adhesion between the 1 st HC layer and the 2 nd HC layer, it is preferable that the 1 st HC layer has the 2 nd HC layer on the surface thereof, that is, both layers are in contact with at least a part of the film surface.

The 1 st HC layer and the 2 nd HC layer may be 1 layer, or may be 2 or more layers, and preferably are 1 layer.

As will be described in detail later, when the antireflection laminate of the present invention is used in a touch panel, the 2HC layer is preferably disposed on the front surface side of the image display device, but the 2HC layer is preferably disposed on the front surface side, particularly the outermost surface side, of the antireflection laminate in order to improve the abrasion resistance and punching property of the surface of the antireflection laminate.

< curable composition for Forming No. 1HC layer and No. 1HC layer >

The 1 st HC layer used in the present invention is formed of the 1 st HC layer-forming curable composition.

The 1 st HC layer-forming curable composition contains a polymerizable compound 1 having a radical polymerizable group and a polymerizable compound 2 having a cation polymerizable group and a radical polymerizable group in the same molecule and being different from the polymerizable compound 1, and the content of the polymerizable compound 2 in the polymerizable compounds contained in the 1 st HC layer-forming curable composition is 51 mass% or more.

(polymerizable Compound)

The description of the radical polymerizable compound is preferably applied to the polymerizable compound 1, and the description of the component a) in the cationic polymerizable compound is preferably applied to the polymerizable compound 2.

The 1 st HC layer-forming curable composition may have another polymerizable compound different from the polymerizable compound 1 and the polymerizable compound 2.

The other polymerizable compound is preferably a polymerizable compound having a cationically polymerizable group. The above-mentioned cationically polymerizable group has the same meaning as the cationically polymerizable group described in the component 2a) of the polymerizable compound, and the preferable range is also the same. In particular, in the present invention, the other polymerizable compound is preferably a compound containing a nitrogen-containing heterocycle containing a cationically polymerizable group. By using such a compound, the adhesion between the resin film and the 1 st HC layer can be more effectively improved. Examples of the nitrogen-containing heterocyclic ring include nitrogen-containing heterocyclic rings selected from the group consisting of a isocyanurate ring and a thiourea ring, and a isocyanurate ring is more preferable. The number of cationic groups contained in the other polymerizable compound is preferably 1 to 10, more preferably 2 to 5. When a polymerizable compound having a cationically polymerizable group and a nitrogen-containing heterocyclic structure is used as the other polymerizable compound, the resin film is preferably a resin film containing an acrylic resin film. With such a configuration, the adhesion between the resin film and the 1 st HC layer tends to be further improved.

Specific examples of the other polymerizable compounds include the above-mentioned exemplified compounds, but the present invention is not limited to the above-mentioned specific examples.

< composition for Forming No. 2HC layer and No. 2HC layer >

The 2 nd HC layer is formed of the curable composition for forming the 2 nd HC layer.

The curable composition for forming a2 nd HC layer contains 90 mass% or more of a polymerizable compound 3 having a radical polymerizable group. The above-mentioned radical polymerizable compound is preferably used as the polymerizable compound 3.

(others)

The above-mentioned descriptions of the polymerization initiator, inorganic particles, matte particles, ultraviolet absorber, fluorine-containing compound, solvent, and other components can be preferably applied.

In particular, in the embodiment in which the HC layer 1A includes the 1 st HC layer and the 2 nd HC layer in this order from the resin film 2A side, the curable composition for forming the HC layer forming the 1 st HC layer preferably contains a solvent, and the curable composition for forming the HC layer forming the 2 nd HC layer preferably contains an antifouling agent.

(thickness of HC layer)

From the viewpoint of reducing keyboard transfer by suppressing deformation of the film, the thickness of the HC layer is preferably 5 μm or more, and more preferably 10 μm or more. From the viewpoint of suppressing curling due to volume shrinkage at the time of HC layer formation, it is preferably 40 μm or less, and more preferably 30 μm or less.

Method for forming-HC layer

The HC layer can be formed by applying the curable composition for forming an HC layer directly on the resin film or via another layer such as an easy-to-adhere layer, and irradiating the resin film with active energy rays. The coating can be performed by a known coating method such as a dip coating method, an air knife coating method, a curtain coating method, a roll coating method, a die coating method, a wire bar coating method, or a gravure coating method. Further, by applying two or more compositions having different compositions simultaneously or sequentially, the HC layer can be formed as a laminated HC layer having two or more layers (for example, about two to five layers).

The applied curable composition for forming an HC layer can be irradiated with active energy rays to form an HC layer. For example, when the curable composition for forming an HC layer contains a radical polymerizable compound, a cation polymerizable compound, a radical photopolymerization initiator, and a cation photopolymerization initiator, the polymerization reaction of the radical polymerizable compound and the cation polymerizable compound can be initiated by the action of the radical photopolymerization initiator and the cation photopolymerization initiator, respectively. The wavelength of the light to be irradiated may be determined depending on the types of the polymerizable compound and the polymerization initiator used. Examples of the light source for light irradiation include a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a chemical lamp, and an electrodeless discharge lamp that emit light in a wavelength band of 150 to 450nmA lamp, an LED (light emitting diode), and the like. The light irradiation amount is usually 30 to 3000mJ/cm²Preferably in the range of 100 to 1500mJ/cm²The range of (1). One or both of before and after the light irradiation may be subjected to a drying treatment as required. The drying treatment can be performed by blowing warm air, placing in a heating furnace, transporting in a heating furnace, or the like. When the curable composition for forming an HC layer contains a solvent, the heating temperature is not particularly limited as long as the heating temperature is a temperature at which the solvent can be dried and removed. The heating temperature is the temperature of warm air or the ambient temperature in the heating furnace.

(4) Inorganic oxide layer (AR layer)

The laminate of the present invention may further have an inorganic oxide layer (AR layer), and for example, an embodiment in which the inorganic oxide layer (AR layer) is provided on the surface opposite to the surface on the side of the support having the hard coat layer is mentioned.

As an embodiment of the laminate having an AR layer, as shown in fig. 2, there is a laminate 4B of the present invention having a structure in which an AR layer 5A, HC, a resin film 2A, and a buffer layer 3A are sequentially laminated.

The AR layer in the laminate of the present invention is a layer having a function as an antireflection layer, and can be formed by a dry coating method such as a sputtering method, a reactive sputtering method, a vapor deposition method, an ion plating method, or a Chemical Vapor Deposition (CVD) method. Since the film thickness uniformity is high and defects such as pores are reduced, a sputtering method capable of forming a thin film having excellent visibility, compactness, and excellent mechanical properties such as scratch resistance is preferably used. Among them, from the viewpoint of achieving high productivity by a higher film formation rate and high discharge stability, a Dual Magnetron Sputtering (DMS) method of forming a film by voltage application in an intermediate frequency region is most suitable.

In addition, when the sputtering method is used, the pressure when the AR layers are laminated is preferably 0.1 to 0.6 Pa. The reason for this is that a sufficient sputtering rate and film density can be obtained.

The AR layer may be either one of a high refractive index layer and a low refractive index layer, and may be a single layer or a plurality of layers.

When the AR layer is a plurality of layers, the AR layer is preferably a layer in which a high refractive index layer and a low refractive index layer are alternately laminated, and the outermost layer of the AR layer (i.e., the layer disposed on the side most opposite to the HC layer) is preferably a low refractive index layer. The AR layer is a laminate of 4 or more layers in which high refractive index layers and low refractive index layers are alternately laminated, and the outermost layer of the AR layer is preferably a low refractive index layer, and the innermost layer of the AR layer (i.e., the layer disposed on the side closest to the HC layer) is more preferably a high refractive index layer.

Examples of the material constituting the high refractive index layer include metals such as indium, tin, titanium, zinc, zirconium, niobium, magnesium, bismuth, cerium, tantalum, aluminum, germanium, potassium, antimony, neodymium, lanthanum, thorium, and hafnium, 2 or more kinds of alloys including these metals, and oxides, fluorides, cured products, and nitrides thereof. Specific examples thereof include titanium oxide, niobium oxide, zirconium oxide, tantalum oxide, zinc oxide, indium oxide, cerium oxide, and the like, but are not limited thereto. When a plurality of layers are stacked, the same material does not necessarily have to be selected, and may be appropriately selected according to the purpose. Among them, in the case of using the sputtering method, niobium oxide is preferable because the produced thin film has a small number of pores.

Examples of the material constituting the low refractive index layer include, but are not limited to, silicon oxide, magnesium fluoride, barium fluoride, calcium fluoride, hafnium fluoride, and lanthanum fluoride. When a plurality of layers are stacked, the same material does not necessarily have to be selected, and may be appropriately selected according to the purpose. In particular, silicon oxide is the most suitable material in view of optical characteristics, mechanical strength, cost, and suitability for film formation. In addition, silicon oxide (SiO) is referred to herein_x) Mainly silicon dioxide (SiO)₂). Wherein SiO is depleted and/or increased by oxygen_xX of (a) varies within a range of 1.8 to 2.2.

The total film thickness of the AR layer is preferably 100 to 300 nm. The lower limit value is preferably not less than the above-described lower limit value from the viewpoint of obtaining sufficient reflection performance, and the upper limit value is preferably not more than the above-described upper limit value from the viewpoint of productivity.

(5) Other layers

The laminate of the present invention may have other layers such as an antifouling layer and an adhesive layer as necessary, in addition to the resin film, the buffer layer, the HC layer, and the AR layer.

(antifouling layer)

The laminate of the present invention may have an antifouling layer on the outermost layer of the AR layer. The antifouling layer is preferably a layer containing a fluorine compound formed by a vacuum deposition method, and more preferably a layer formed using a fluorine-containing silicon compound having 2 or more silicon atoms bonded to a reactive functional group. The reactive functional group is a group that reacts with the outermost layer of the AR layer and can bond thereto. It is also preferable to form the antifouling layer by using a fluorine-containing silicon compound having reactive functional groups and reacting the reactive functional groups with each other.

By providing the antifouling layer, stains are less likely to adhere to the surface, and the wiping performance when stains adhere thereto can be improved. Among these, the method for forming the antifouling layer is not particularly limited, but a film forming method by a vacuum deposition method is preferable. With this method, when the film is continuously formed, the film can be formed with good uniformity of film thickness.

In this case, in order to have sufficient antifouling performance, it is preferable that at least the water droplet contact angle is 100 ° or more. This can improve the wiping property of stains on the surface. In addition, the coefficient of friction is also reduced, and therefore the scratch resistance can be further improved. Further, from the viewpoint of scratch resistance, it is particularly preferable to use steel wool #0000 for the stain-resistant layer so as to have a load of 1.5kg/cm²In an environment of 25 ℃ and 55% relative humidity, no scratch occurs even if the wiping is repeated 10 times.

[ article comprising laminate ]

Examples of articles including the laminate of the present invention include various articles in which inhibition of transfer of the shape of another object onto the hard coat layer (for example, inhibition of keyboard transfer) is required in various industries such as home electronics industry, electronic and electrical industry, automobile industry, and housing industry. Specific examples thereof include image display devices such as notebook PCs, touch sensors, touch panels, and liquid crystal display devices, automobile window glasses, and residential window glasses. By providing the laminate of the present invention on such an article, it is possible to provide an article in which transfer of the shape of another object to the hard coat layer (for example, keyboard transfer) is sufficiently suppressed. Further, when a laminate having an AR layer is used, an antireflection function can be provided. The laminate of the present invention is preferably used as a protective film for an image display device, a polarizing plate, or a laminate used in a front panel, and more preferably used as a protective film for an image display element of a notebook PC, a polarizing plate, or a laminate used in a front panel.

Note that the notebook PC to which the laminate of the present invention can be applied is not particularly limited, and can be appropriately selected according to the purpose.

Image display device

An image display device having the laminate of the present invention includes, for example, a protective film, a polarizing plate or a front panel, and an image display element, each of which includes the laminate of the present invention.

As the image display device, it can be used for a liquid crystal display device (LC D), a plasma display panel, an electroluminescence display, a cathode ray tube display device, and an image display device such as a touch panel.

Examples of the liquid crystal display device include a TN (Twisted Nematic) type, an STN (Super-Twisted Nematic) type, a TSTN (Triple Super-Twisted Nematic) type, a multi-domain type, a VA (Vertical Alignment) type, an IPS (in plane Switching) type, and an OCB (Optically compensated bend) type.

The image display device is improved in brittleness and excellent in handling property, and is preferably capable of reducing light leakage in a damp-heat test without deteriorating display quality due to surface smoothness or wrinkles.

That is, in the image display device having the laminate of the present invention, the image display element is preferably a liquid crystal display element. Examples of an image display device having a liquid crystal display element include the system of Sony Ericsson Cor displacement and Xperia P.

Polarizing plate

The polarizing plate of the present invention is configured such that the laminate of the present invention has a polarizer. The laminate of the present invention may have the buffer layer, the support, and the hard coat layer in this order, and the polarizer may be provided on the surface of the buffer layer opposite to the side having the support, or may have the buffer layer, the support, and the hard coat layer in this order, and the polarizer may be provided on the surface of the hard coat layer opposite to the side having the support.

More specifically, the laminate of the present invention can be used as one or both of the protective films of the polarizing plate comprising a polarizer and protective films disposed on both sides thereof. By using the laminate of the present invention, a polarizing plate in which keyboard transfer accompanying a load is sufficiently suppressed can be provided. Further, when a laminate having an AR layer is used, an antireflection function can be provided.

Location of setting buffer layer

In the image display device having the laminate of the present invention, the position where the buffer layer is provided is not particularly limited, and examples thereof include the following embodiments.

Functional layer/support/buffer layer

Functional layer/support/buffer layer/protective film

Functional layer/support/buffer layer/protective film/polarizer/protective film

Functional layer/support/buffer layer/polarizer/protective film

Functional layer/support/polarizer/buffer layer/protective film

Functional layer/support/polarizer/protective film/buffer layer

Functional layer/support/buffer layer/adhesive/protective film/polarizer/protective film

Functional layer/support/polarizer/protective film/adhesive/buffer layer

Functional layer/support/retardation film/buffer layer

Functional layer/support/retardation film/adhesive/buffer layer

Functional layer/support/retardation film/buffer layer/protective film

Functional layer/support/phase difference film/buffer layer/protective film/polarizer/protective film

Functional layer/support/phase difference film/adhesive/protective film/buffer layer/polarizer/protective film

Functional layer/support/phase difference film/adhesive/protective film/buffer layer/adhesive/polarizer/protective film

The laminate of the present invention may be used as one of the protective films, and a general cellulose acetate film may be used for the other protective film. In this case, it is preferable to use a cellulose acetate film which is produced by a solution film-forming method and which is stretched in the width direction in a roll film form at a stretch ratio of 10 to 100%.

Further, of the 2 protective films for polarizers, an optical compensation film having an optical compensation layer including an optically anisotropic layer is also a preferable embodiment, except for the laminate of the present invention. The optical compensation film (retardation film) can improve the viewing angle characteristics of a liquid crystal display screen. As the optical compensation film, a known film can be used, but from the viewpoint of widening the viewing angle, the optical compensation film described in japanese patent application laid-open No. 2001-100042 is preferable.

The polarizer includes an iodine-based polarizer, a dye-based polarizer using a 2-color dye, or a polyene-based polarizer. Iodine-based polarizers and dye-based polarizers are generally produced using polyvinyl alcohol-based films.

As the polarizer, a polarizer cut out from a known polarizer or from a long polarizer whose absorption axis is neither parallel nor perpendicular to the longitudinal direction of the polarizer may be used. The long polarizer having the absorption axis of the polarizer neither parallel nor perpendicular to the longitudinal direction was produced by the following method.

That is, the polymer film such as a polyvinyl alcohol film continuously supplied is stretched by applying tension while holding both ends thereof by a holding means, and is stretched at least 1.1 to 20.0 times in the film width direction. And then, the film is manufactured by a stretching method in which the film conveying direction is bent while the both ends of the film are held, so that the difference in the speed of the holding devices at the both ends of the film in the longitudinal direction is within 3%, and the angle formed between the film conveying direction and the substantial stretching direction of the film at the outlet of the step of holding the both ends of the film is inclined to 20 to 70 °. In particular, from the viewpoint of productivity, it is preferable to use an elongation method in which the angle between the film transport direction and the substantial elongation direction of the film at the outlet of the step of holding both ends of the film is inclined by 45 °.

The method of stretching a polymer film can be applied to the methods described in paragraphs 0020 to 0030 of Japanese patent application laid-open No. 2002-086554.

Examples

The present invention will be described in further detail below with reference to examples. The present invention is not limited to this and is explained below. In the following examples, "parts" and "%" of the composition are by mass unless otherwise specified.

<1-1. preparation of resin film (TAC film with a thickness of 100 μm) >

A laminated film of 3 cellulose acylate layers of outer layer/core layer/outer layer was produced by the following method.

(1) Preparation of core layer cellulose acylate coating solution

The following composition was put into a stirring tank and stirred, thereby preparing a core layer cellulose acylate coating solution.

(core layer cellulose acylate coating solution)

100 parts by mass of cellulose acetate having an acetyl degree of substitution of 2.88 and a weight-average molecular weight of 260,000

10 parts by mass of a phthalate oligomer represented by the following formula (A-1)

4 parts by mass of a compound represented by the following formula (A-2)

2.7 parts by mass of an ultraviolet absorber represented by the following formula (A-3) (manufactured by BASF)

0.18 part by mass of a light stabilizer (product name: TINUVIN123, manufactured by BASF Corp.)

0.02 parts by mass of N-alkenylpropylenediamine 3 acetic acid (product name: Techlun DO, manufactured by Nagase Chemtex Corporation)

430 parts by mass of methylene chloride (1 st solvent)

64 parts by mass of methanol (No. 2 solvent)

The compounds used are shown below.

The weight average molecular weight of the phthalate oligomer (A-1) having the following structure was 750.

[ chemical formula 11]

[ chemical formula 12]

[ chemical formula 13]

(2) Preparation of outer layer cellulose acylate coating solution

To 90 parts by mass of the above-mentioned core layer cellulose acylate coating solution, 10 parts by mass of the following inorganic particle-containing composition was added to prepare an outer layer cellulose acylate coating solution.

(composition containing inorganic particles)

2 parts by mass of silica particles having an average primary particle diameter of 20nm (NIPPON AEROSIL CO., LTD., product name: AEROSIL R972)

76 parts by mass of methylene chloride (1 st solvent)

11 parts by mass of methanol (No. 2 solvent)

Core layer cellulose acylate coating solution 1 part by mass

(3) Production of resin film

3 kinds of the outer layer cellulose acylate dope solution, the core layer cellulose acylate dope solution and the outer layer cellulose acylate dope solution were simultaneously cast on a casting belt having a surface temperature of 20 ℃ from a casting port in such a manner that the outer layer cellulose acylate dope solutions were disposed on both sides of the core layer cellulose acylate dope solution.

As the casting belt, a stainless steel endless belt having a width of 2.1m and a length of 70m was used. The casting tape was ground to a thickness of 1.5mm and a surface roughness of 0.05 μm or less. A casting belt made of SUS316 and having sufficient corrosion resistance and strength was used. The thickness of the casting belt is not more than 0.5%.

With respect to the obtained casting film, a rapid drying wind having a wind speed of 8m/s, a gas concentration of 16%, and a temperature of 60 ℃ was applied to the surface of the casting film, thereby forming an initial film. Thereafter, a dry air of 140 ℃ was blown from the upstream side of the upper part of the casting belt. Then, 120 ℃ and 60 ℃ dry air were blown from the downstream side.

After the residual solvent amount was set to about 33 mass%, the tape was peeled off. Then, both ends of the obtained film in the width direction were fixed by tenter clips, and the film having a residual solvent amount of 3 to 15 mass% was dried while extending 1.06 times in the transverse direction. Then, the sheet was conveyed between rolls of a heat treatment apparatus and further dried, thereby producing a TAC film having a thickness of 100 μm (outer layer/core layer/outer layer: 3 μm/94 μm/3 μm).

(4) Production of resin film (TAC film having different thicknesses)

TAC films having different thicknesses were produced by the same method as described above, except that the thicknesses were adjusted to 80 μm (outer layer/core layer/outer layer: 3 μm/74 μm/3 μm) and 200 μm (outer layer/core layer/outer layer: 3 μm/194 μm/3 μm).

<1-2. preparation of resin film (PI film 50 μm in thickness) >

(1) Production of polyimide powder

To a 1L reactor equipped with a stirrer, a nitrogen gas injection device, a dropping funnel, a temperature regulator, and a cooler, 832g of N, N-dimethylacetamide (DMAc) was added under a nitrogen gas flow, and then the temperature of the reactor was set to 25 ℃. 64.046g (0.2mol) of bistrifluoromethylbenzidine (TFDB) was added thereto to dissolve the compound, thereby obtaining a solution. While maintaining the obtained solution at 25 ℃, 31.09g (0.07mol) of 2, 2-bis (3, 4-dicarboxyphenyl) hexafluoropropane dianhydrosylate (6FDA) and 8.83g (0.03mol) of biphenyltetracarboxylic acid dianhydrosylate (BPDA) were charged and stirred for a predetermined period of time to react. Thereafter, 20.302g (0.1mol) of terephthaloyl chloride (TPC) was added to the solution to obtain a polyamic acid solution having a solid content of 13% by mass. Then, 25.6g of pyridine and 33.1g of acetic anhydride were put into the polyamic acid solution, and stirred for 30 minutes, further stirred at 70 ℃ for 1 hour, and then cooled to room temperature. 20L of methanol was added thereto, and the precipitated solid component was filtered and pulverized. Thereafter, the resultant was dried at 100 ℃ for 6 hours under vacuum to obtain 111g of a polyimide as a solid powder.

(2) Production of resin film

100g of polyimide as a solid powder was dissolved in 670g of N, N-dimethylacetamide (DMAc) to obtain a 13 mass% solution. The resulting solution was cast on a stainless steel plate so that the thickness after heating became 50 μm, and dried with hot air at 130 ℃ for 30 minutes. Thereafter, the film was peeled off from the stainless steel plate, fixed to a frame by a pin, and the frame to which the film was fixed was put into a vacuum oven, heated for 2 hours while gradually increasing the heating temperature from 100 ℃ to 300 ℃, and then gradually cooled. After the cooled film was separated from the frame, a final heat treatment step was performed at 300 ℃ for 30 minutes to prepare a polyimide film having a thickness of 50 μm.

(3) Production of resin film (PI film having different thicknesses)

A polyimide film having a thickness of 80 μm was produced in the same manner as described above.

<2-1. preparation of curable composition for Forming hard coat layer (HC layer) >

The components were mixed in the formulation shown in Table 1 below, and the mixture was filtered through a polypropylene filter having a pore size of 10 μm to prepare curable compositions B-1 to B-4 for HC layer formation.

[ Table 1]

In table 1, the blending ratio is described in parts by mass. And "-" means that the component is not contained.

The details of each compound described in table 1 are shown below.

< radically polymerizable Compound >

KAYARAD DPHA: mixtures of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (Nippon Kayaku Co., manufactured by Ltd., product name)

LIGHT ESTER 2 EG: diethylene glycol dimethacrylate (Kyoeisha chemical Co., Ltd., product name, manufactured by Ltd.)

< cationically polymerizable Compound >

CYCLOMER M100: 3, 4-epoxycyclohexylmethyl methacrylate (Daicel Corporation Co., Ltd., product name, manufactured by Ltd.)

< silica particles >

MEK-AC-2140Z: (product name of spherical silica particles having an average primary particle diameter of 10 to 20nm manufactured by Nissan Chemical Industries, LTD.)

< polymerization initiator >

Irg184 Irg 1-hydroxy-cyclohexyl-phenyl-ketone (α -hydroxyalkylphenylacetic acid based radical photopolymerization initiator, product name IRGACURE184 available from BASF corporation)

CPI-100P: triarylsulfonium salt-based photo-cationic polymerization initiator (San-Apro Ltd., product name)

< fluorine-containing Compound >

RS 90: fluorine-containing oligomer having radical polymerizable group (DIC Corporation)

< solvent >

MEK: methyl ethyl ketone

MIBK: methyl isobutyl ketone

<3-1 preparation of coating liquids C-1 to C-5 for Forming buffer layer >

Compositions C-1 to C-4 for forming a cushion layer were prepared by mixing the respective components in the compositions shown in Table 2 below and filtering the mixture through a polypropylene filter having a pore size of 10 μm.

[ Table 2]

In table 2, "-" indicates that the component is not contained.

Details of the compounds described in table 2 are shown below.

< elastomer >

KURARITY LA2140e, KURARITY LA2250, KURARITY LA 4285: PMMA-PnBA copolymer elastomer (Kuraray Co., Ltd., product name, manufactured by Ltd.)

VYLON UR 2300: polyurethane modified polyester (TOYOBO CO., Ltd., product name)

HYBRAR 7311: hydrogen additive for styrene-vinyl isoprene Block copolymer (Kuraray Co., Ltd., product name, manufactured by Ltd.)

[ example 1]

<4> preparation of laminate

<4-1. formation of hard coat layer (HC layer) >

The curable composition B-1 for forming an HC layer was applied to one surface of the TAC film having a thickness of 100 μm prepared as described above, and cured to form an HC layer having a thickness of 10 μm, thereby preparing a resin film having an HC layer.

The coating and curing method is specifically as follows. The curable composition for forming an HC layer was applied by a die coating method using a slit die described in example 1 of Japanese patent application laid-open No. 2006-122889 at a transport speed of 30 m/min, and dried at an ambient temperature of 60 ℃ for 150 seconds. Then, a 160W/cm air-cooled metal halide lamp (EYEGRAPHICS CO., LTD., manufactured) was further used at an oxygen concentration of about 0.1 vol% under a nitrogen purge with an irradiation illuminance of 300mW/cm²The dose of irradiation was 600mJ/cm²The applied curable composition for forming an HC layer is cured by the ultraviolet ray of (2) to form an HC layer, and then the HC layer is wound up.

<4-2. formation of buffer layer >

The surface of the support having the HC layer formed thereon opposite to the HC layer was coated with the composition C-1 for forming a buffer layer, and dried to form a buffer layer.

The coating and drying methods are specifically as follows. The laminate of example 1 was produced by applying the composition for forming a buffer layer to a substrate by a die coating method using a slit die described in example 1 of jp 2006-122889 a at a transport speed of 30 m/min so that the film thickness of the composition becomes 50 μm, and drying the composition at an ambient temperature of 120 ℃ for 120 seconds.

[ examples 2 and 3]

Laminates of examples 2 and 3 were produced in the same manner as in example 1 except that the compositions for forming a buffer layer C-1 and C-2 and C-3 were used instead of the composition for forming a buffer layer.

[ examples 4 to 6]

Laminates of examples 4 to 6 were produced in the same manner as in example 2 except that the buffer layers were each 10 μm, 25 μm, and 100 μm thick.

[ examples 7, 8, 13, and 14]

Laminates of examples 7, 8, 13 and 14 were produced in the same manner as in example 2 except that TAC films having thicknesses of 80 μm and 200 μm and PI films having thicknesses of 50 μm and 80 μm were used instead of TAC films having a thickness of 100 μm, respectively.

[ examples 9 to 11]

Laminates according to examples 9 to 11 were produced in the same manner as in example 2 except that the curable compositions B-2 to B-4 for forming an HC layer were used instead of the curable composition B-1 for forming an HC layer.

[ example 12]

A laminate of example 12 was produced in the same manner as in example 2, except that the thickness of the HC layer was changed to 5 μm.

[ examples 15 and 16]

Laminates of examples 15 and 16 were produced in the same manner as in examples 2 and 10, except that the inorganic oxide layer (AR layer) was formed on the HC layer of the HC layer-attached resin film.

Specifically, the AR layer is formed by sputtering under any film formation pressure so that the layer structure is Nb from the HC layer side₂O₅/SiO₂/Nb₂O₅/SiO₂The film was formed so that the film thickness of each layer became 15nm/25nm/105nm/85 nm.

Comparative example 1

A laminate of comparative example 1 was produced in the same manner as in example 1, except that the buffer layer was not provided.

Comparative example 2

A laminate of comparative example 2 was produced in the same manner as in example 1, except that the composition for forming a buffer layer C-4 was used instead of the composition for forming a buffer layer C-1.

Comparative example 3

A laminate of comparative example 3 was produced in the same manner as in example 1 except that 2 sheets of a 25 μm thick adhesive (product name: SK-2057, manufactured by ltd.) were laminated instead of the composition C-1 for forming a cushion layer and that the composition C-5 for forming a cushion layer was used instead of the composition C-1 for forming a cushion layer.

(measurement of storage modulus and dissipation modulus and derivation of the maximum value of tan. delta. and the frequency representing the maximum value)

The storage modulus at 25 ℃, the dissipation modulus, the maximum value of tan δ and the frequency representing the maximum value of the buffer layer were measured and derived by the above-described method.

Fig. 3 shows the results obtained by plotting the tan δ dependence of each obtained sample with respect to the frequency at 25 ℃.

< test >

The following test was performed on the laminate produced as described above. The test results are summarized and described in table 3 below.

(transfer of shape of other object on hard coat layer (keyboard transfer))

The optical film (laminate) was bonded to a glass plate (transverse 280mm × longitudinal 180mm × thickness 0.5mm) on the buffer layer side via an adhesive (SK-2057, product name, manufactured by Soken Chemical & Engineering co., ltd., etc.) having a thickness of 20 μm while applying a load of 2kg with a rubber roller.

The glass plate to which the laminate was bonded was fixed with a tape or the like so that the glass plate was connected to a display of a laptop computer (Macbook, manufactured by applei inc.), placed on a vibration tester (imvcorport, m060) in a state where the notebook PC was closed, placed on the notebook PC by 10kg, fixed so that the notebook PC was not moved in the X-Y direction, and then vibrated in the Z-axis direction for 180 minutes under the random vibration test scale 1 described in JIS Z0232. The X-Y direction refers to the in-plane direction of the laminate, and the Z-axis direction refers to a direction orthogonal to the in-plane direction of the laminate.

After the vibration was completed, the sample was taken out, and the degree of scratches and dents generated by the keyboard was evaluated according to the following criteria.

A: no dents or scratches were observed at all.

B: some dents or scratches were observed, but there was no problem in use.

C: a part of dents or scratches can be observed, but there is no problem in use.

D: there are problems in that a dent or a scratch which can be observed is locally generated and used.

E: a dent or a scratch which can be observed is generated on the whole surface and has a problem in use.

(falling ball resistance)

A2 kg load was applied to the glass plate with a rubber roller through an adhesive (SK-2057, product name: Soken Chemical & Engineering Co., Ltd.) having a thickness of 20 μm so that the cushion layer side was opposed to the glass plate, and the glass plate (product name: EAGLE XG, thickness 0.4mm, manufactured by Corning Corp.) and the laminate produced above were bonded.

The glass plate to which the laminate was bonded was placed on a base made of stainless steel so that the glass plate was in contact with the base, and then iron balls (3.3 cm in diameter and 150g in mass) were brought from a predetermined height and collided so that the HC layer (AR layer in the laminate having the AR layer formed) of the laminate was in contact with the iron balls.

Then, the glass plate was observed, and the highest value among the heights at which no crack, or the like was observed was defined as the impact resistance height (cm).

As shown in table 3, the laminate of the example sufficiently suppressed the transfer of the shape of another object to the hard coat layer (keyboard transfer), and also had excellent resistance to falling balls.

In the laminate of comparative example 1 having no cushion layer, the shape of the other object was inferior in both transfer (keyboard transfer) to the hard coat layer and resistance to falling balls. In addition, the laminates of comparative examples 2 and 3, which had a cushion layer or an acrylic adhesive made of a urethane resin having a tan δ maximum value out of the predetermined frequency range of the present invention, had no problem in the falling ball resistance, but could not suppress the transfer of the shape of another object to the hard coat layer (keyboard transfer).

When the laminate of the present invention is used for a polarizing plate, it is considered that the polarizing plate can sufficiently suppress transfer of the shape of another object to the hard coat layer (keyboard transfer) and exhibits excellent resistance to falling balls.

Description of the symbols

1A-hard coat layer (HC layer), 2A-support, 3A-buffer layer, 4A, 4B-laminate, 5A-inorganic oxide layer (AR layer).

Claims (9)

1. A laminate having a cushion layer, a support and a hard coat layer, wherein in the laminate,

the buffer layer is at 25 ℃ at a frequency of 10⁴～10¹³The range of Hz has a maximum value of tan delta,

wherein the tan delta is a ratio of a dissipation modulus to a storage modulus.

2. The laminate according to claim 1, wherein,

the maximum value of tan δ is 0.1 or more.

3. The laminate according to claim 1 or 2,

the storage modulus of the buffer layer at a frequency at which the maximum value of tan δ is exhibited is 30MPa or more.

4. The laminate according to any one of claims 1 to 3,

the thickness of the buffer layer is 10-200 mu m.

5. The laminate according to any one of claims 1 to 4,

the buffer layer comprises a block copolymer of methyl methacrylate and n-butyl acrylate.

6. The laminate according to any one of claims 1 to 5, further comprising an inorganic oxide layer.

7. The laminate according to any one of claims 1 to 6,

the hard coat layer contains a cured product of a polymerizable compound.

8. A polarizing plate, wherein the laminate of any one of claims 1 to 7 has a polarizer.

9. An image display device having the laminate according to any one of claims 1 to 7, or the polarizing plate according to claim 8.

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